diff --git a/lib/ui/platform_dispatcher.dart b/lib/ui/platform_dispatcher.dart
index fb689148aaee5..f955bb5f1882d 100644
--- a/lib/ui/platform_dispatcher.dart
+++ b/lib/ui/platform_dispatcher.dart
@@ -390,8 +390,9 @@ class PlatformDispatcher {
   // If this value changes, update the encoding code in the following files:
   //
   //  * pointer_data.cc
+  //  * pointer.dart
   //  * AndroidTouchProcessor.java
-  static const int _kPointerDataFieldCount = 37;
+  static const int _kPointerDataFieldCount = 36;
 
   static PointerDataPacket _unpackPointerDataPacket(ByteData packet) {
     const int kStride = Int64List.bytesPerElement;
@@ -437,7 +438,6 @@ class PlatformDispatcher {
         panDeltaY: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
         scale: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
         rotation: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
-        viewId: packet.getInt64(kStride * offset++, _kFakeHostEndian),
         preferredStylusAuxiliaryAction: PointerPreferredStylusAuxiliaryAction.values[packet.getInt64(kStride * offset++, _kFakeHostEndian)],
       ));
       assert(offset == (i + 1) * _kPointerDataFieldCount);
diff --git a/lib/ui/pointer.dart b/lib/ui/pointer.dart
index 0414e563a7543..4585fbcbf0a87 100644
--- a/lib/ui/pointer.dart
+++ b/lib/ui/pointer.dart
@@ -197,7 +197,6 @@ class PointerData {
     this.panDeltaY = 0.0,
     this.scale = 0.0,
     this.rotation = 0.0,
-    this.viewId = 0,
     this.preferredStylusAuxiliaryAction = PointerPreferredStylusAuxiliaryAction.ignore,
   });
 
@@ -397,9 +396,6 @@ class PointerData {
   /// The current angle of the pan/zoom in radians, with 0.0 as the initial angle.
   final double rotation;
 
-  /// The ID of the view that this event took place.
-  final int viewId;
-
   /// For events with signal kind of stylusAuxiliaryAction
   ///
   /// The current preferred action for stylusAuxiliaryAction, with ignore as the default.
@@ -445,7 +441,6 @@ class PointerData {
              'panDeltaY: $panDeltaY, '
              'scale: $scale, '
              'rotation: $rotation, '
-             'viewId: $viewId, '
              'preferredStylusAuxiliaryAction: $preferredStylusAuxiliaryAction'
            ')';
   }
diff --git a/lib/ui/window/pointer_data.h b/lib/ui/window/pointer_data.h
index fbd9b519b0bf6..1dc159554ad74 100644
--- a/lib/ui/window/pointer_data.h
+++ b/lib/ui/window/pointer_data.h
@@ -9,9 +9,9 @@
 
 namespace flutter {
 
-// If this value changes, other places need changing too. See
-// _kPointerDataFieldCount in platform_dispatcher.dart.
-static constexpr int kPointerDataFieldCount = 37;
+// If this value changes, update the pointer data unpacking code in
+// platform_dispatcher.dart.
+static constexpr int kPointerDataFieldCount = 36;
 static constexpr int kBytesPerField = sizeof(int64_t);
 // Must match the button constants in events.dart.
 enum PointerButtonMouse : int64_t {
@@ -110,7 +110,6 @@ struct alignas(8) PointerData {
   double pan_delta_y;
   double scale;
   double rotation;
-  int64_t view_id;
   PreferredStylusAuxiliaryAction preferred_auxiliary_stylus_action;
 
   void Clear();
diff --git a/lib/web_ui/lib/pointer.dart b/lib/web_ui/lib/pointer.dart
index b20f45c2864f3..fd7981bc354a7 100644
--- a/lib/web_ui/lib/pointer.dart
+++ b/lib/web_ui/lib/pointer.dart
@@ -89,7 +89,6 @@ class PointerData {
     this.panDeltaY = 0.0,
     this.scale = 0.0,
     this.rotation = 0.0,
-    this.viewId = 0,
     this.preferredStylusAuxiliaryAction = PointerPreferredStylusAuxiliaryAction.ignore,
   });
   final int embedderId;
@@ -127,7 +126,6 @@ class PointerData {
   final double panDeltaY;
   final double scale;
   final double rotation;
-  final int viewId;
   final PointerPreferredStylusAuxiliaryAction preferredStylusAuxiliaryAction;
 
   @override
@@ -168,7 +166,6 @@ class PointerData {
            'panDeltaY: $panDeltaY, '
            'scale: $scale, '
            'rotation: $rotation, '
-           'viewId: $viewId, '
            'preferredStylusAuxiliaryAction: $preferredStylusAuxiliaryAction'
            ')';
   }
diff --git a/shell/platform/android/io/flutter/embedding/android/AndroidTouchProcessor.java b/shell/platform/android/io/flutter/embedding/android/AndroidTouchProcessor.java
index 3f72c98c899c0..ea36686e7c8b7 100644
--- a/shell/platform/android/io/flutter/embedding/android/AndroidTouchProcessor.java
+++ b/shell/platform/android/io/flutter/embedding/android/AndroidTouchProcessor.java
@@ -94,9 +94,8 @@ public class AndroidTouchProcessor {
     int UNKNOWN = 4;
   }
 
-  // If this value changes, other places need changing too. See
-  // _kPointerDataFieldCount in platform_dispatcher.dart.
-  private static final int POINTER_DATA_FIELD_COUNT = 37;
+  // Must match the unpacking code in hooks.dart.
+  private static final int POINTER_DATA_FIELD_COUNT = 36;
   @VisibleForTesting static final int BYTES_PER_FIELD = 8;
 
   // This value must match the value in framework's platform_view.dart.
@@ -239,8 +238,6 @@ private void addPointerForIndex(
       int pointerData,
       Matrix transformMatrix,
       ByteBuffer packet) {
-    // TODO(dkwingsmt): Get the source view ID from event data.
-    int viewId = 0;
     if (pointerChange == -1) {
       return;
     }
@@ -376,8 +373,6 @@ private void addPointerForIndex(
     packet.putDouble(1.0); // scale
     packet.putDouble(0.0); // rotation
 
-    packet.putLong(viewId); // viewId
-
     packet.putLong(PointerPreferredStylusAuxiliaryAction.IGNORE); // preferred stylus action
 
     if (isTrackpadPan && getPointerChangeForPanZoom(pointerChange) == PointerChange.PAN_ZOOM_END) {
diff --git a/shell/platform/darwin/macos/framework/Headers/FlutterEngine.h b/shell/platform/darwin/macos/framework/Headers/FlutterEngine.h
index a7b6dd7288e12..7c7bea715893b 100644
--- a/shell/platform/darwin/macos/framework/Headers/FlutterEngine.h
+++ b/shell/platform/darwin/macos/framework/Headers/FlutterEngine.h
@@ -26,7 +26,7 @@
  * backward compatibility, single-view APIs will always operate on the view with
  * this ID. Also, the first view assigned to the engine will also have this ID.
  */
-extern const int64_t kFlutterDefaultViewId;
+extern const uint64_t kFlutterDefaultViewId;
 
 @class FlutterViewController;
 
diff --git a/shell/platform/darwin/macos/framework/Headers/FlutterPluginRegistrarMacOS.h b/shell/platform/darwin/macos/framework/Headers/FlutterPluginRegistrarMacOS.h
index 025edd638b3c6..39fbba1b43bd3 100644
--- a/shell/platform/darwin/macos/framework/Headers/FlutterPluginRegistrarMacOS.h
+++ b/shell/platform/darwin/macos/framework/Headers/FlutterPluginRegistrarMacOS.h
@@ -4,8 +4,6 @@
 
 #import <Cocoa/Cocoa.h>
 
-#include <stdint.h>
-
 #import "FlutterBinaryMessenger.h"
 #import "FlutterChannels.h"
 #import "FlutterMacros.h"
@@ -13,9 +11,6 @@
 #import "FlutterPluginMacOS.h"
 #import "FlutterTexture.h"
 
-typedef int64_t FlutterViewId;
-constexpr int64_t kFlutterDefaultViewId = 0;
-
 // TODO: Merge this file and FlutterPluginMacOS.h with the iOS FlutterPlugin.h, sharing all but
 // the platform-specific methods.
 
@@ -52,7 +47,7 @@ FLUTTER_DARWIN_EXPORT
 /**
  * The `NSView` associated with the given view ID, if any.
  */
-- (nullable NSView*)viewForId:(int64_t)viewId;
+- (nullable NSView*)viewForId:(uint64_t)viewId;
 
 /**
  * Registers |delegate| to receive handleMethodCall:result: callbacks for the given |channel|.
diff --git a/shell/platform/darwin/macos/framework/Headers/FlutterViewController.h b/shell/platform/darwin/macos/framework/Headers/FlutterViewController.h
index 22708b565a3cc..eb3c0a0f5984a 100644
--- a/shell/platform/darwin/macos/framework/Headers/FlutterViewController.h
+++ b/shell/platform/darwin/macos/framework/Headers/FlutterViewController.h
@@ -61,7 +61,7 @@ FLUTTER_DARWIN_EXPORT
  * If the view controller is unattached (see FlutterViewController#attached),
  * reading this property throws an assertion.
  */
-@property(nonatomic, readonly) int64_t viewId;
+@property(nonatomic, readonly) uint64_t viewId;
 
 /**
  * The style of mouse tracking to use for the view. Defaults to
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
index 2e3828016174d..575742df2c8ef 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
@@ -49,7 +49,7 @@ class FlutterCompositor {
 
   // Presents the FlutterLayers by updating the FlutterView specified by
   // `view_id` using the layer content. Sets frame_started_ to false.
-  bool Present(int64_t view_id, const FlutterLayer** layers, size_t layers_count);
+  bool Present(uint64_t view_id, const FlutterLayer** layers, size_t layers_count);
 
  private:
   void PresentPlatformViews(FlutterView* default_base_view,
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
index 890114de9d5da..96acf4bb2a189 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
@@ -37,7 +37,9 @@
   return true;
 }
 
-bool FlutterCompositor::Present(int64_t view_id, const FlutterLayer** layers, size_t layers_count) {
+bool FlutterCompositor::Present(uint64_t view_id,
+                                const FlutterLayer** layers,
+                                size_t layers_count) {
   FlutterView* view = [view_provider_ viewForId:view_id];
   if (!view) {
     return false;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositorTest.mm b/shell/platform/darwin/macos/framework/Source/FlutterCompositorTest.mm
index 8755ae3f14132..4005b176aaf24 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositorTest.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositorTest.mm
@@ -11,7 +11,7 @@
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterViewProvider.h"
 #import "flutter/testing/testing.h"
 
-extern const int64_t kFlutterDefaultViewId;
+extern const uint64_t kFlutterDefaultViewId;
 
 @interface FlutterViewMockProvider : NSObject <FlutterViewProvider> {
   FlutterView* _defaultView;
@@ -32,7 +32,7 @@ - (nonnull instancetype)initWithDefaultView:(nonnull FlutterView*)view {
   return self;
 }
 
-- (nullable FlutterView*)viewForId:(int64_t)viewId {
+- (nullable FlutterView*)viewForId:(uint64_t)viewId {
   if (viewId == kFlutterDefaultViewId) {
     return _defaultView;
   }
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
index 41cce6095775d..864049ff90452 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
@@ -25,6 +25,8 @@
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterViewController_Internal.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterViewEngineProvider.h"
 
+const uint64_t kFlutterDefaultViewId = 0;
+
 NSString* const kFlutterPlatformChannel = @"flutter/platform";
 
 /**
@@ -88,7 +90,7 @@ @interface FlutterEngine () <FlutterBinaryMessenger>
  */
 @property(nonatomic, strong) NSMutableArray<NSNumber*>* isResponseValid;
 
-- (nullable FlutterViewController*)viewControllerForId:(int64_t)viewId;
+- (nullable FlutterViewController*)viewControllerForId:(uint64_t)viewId;
 
 /**
  * An internal method that adds the view controller with the given ID.
@@ -96,7 +98,7 @@ - (nullable FlutterViewController*)viewControllerForId:(int64_t)viewId;
  * This method assigns the controller with the ID, puts the controller into the
  * map, and does assertions related to the default view ID.
  */
-- (void)registerViewController:(FlutterViewController*)controller forId:(int64_t)viewId;
+- (void)registerViewController:(FlutterViewController*)controller forId:(uint64_t)viewId;
 
 /**
  * An internal method that removes the view controller with the given ID.
@@ -105,7 +107,7 @@ - (void)registerViewController:(FlutterViewController*)controller forId:(int64_t
  * map. This is an no-op if the view ID is not associated with any view
  * controllers.
  */
-- (void)deregisterViewControllerForId:(int64_t)viewId;
+- (void)deregisterViewControllerForId:(uint64_t)viewId;
 
 /**
  * Shuts down the engine if view requirement is not met, and headless execution
@@ -292,7 +294,7 @@ - (NSView*)view {
   return [self viewForId:kFlutterDefaultViewId];
 }
 
-- (NSView*)viewForId:(int64_t)viewId {
+- (NSView*)viewForId:(uint64_t)viewId {
   FlutterViewController* controller = [_flutterEngine viewControllerForId:viewId];
   if (controller == nil) {
     return nil;
@@ -571,7 +573,7 @@ - (void)loadAOTData:(NSString*)assetsDir {
   }
 }
 
-- (void)registerViewController:(FlutterViewController*)controller forId:(int64_t)viewId {
+- (void)registerViewController:(FlutterViewController*)controller forId:(uint64_t)viewId {
   NSAssert(controller != nil, @"The controller must not be nil.");
   NSAssert(![controller attached],
            @"The incoming view controller is already attached to an engine.");
@@ -581,7 +583,7 @@ - (void)registerViewController:(FlutterViewController*)controller forId:(int64_t
   [_viewControllers setObject:controller forKey:@(viewId)];
 }
 
-- (void)deregisterViewControllerForId:(int64_t)viewId {
+- (void)deregisterViewControllerForId:(uint64_t)viewId {
   FlutterViewController* oldController = [self viewControllerForId:viewId];
   if (oldController != nil) {
     [oldController detachFromEngine];
@@ -595,7 +597,7 @@ - (void)shutDownIfNeeded {
   }
 }
 
-- (FlutterViewController*)viewControllerForId:(int64_t)viewId {
+- (FlutterViewController*)viewControllerForId:(uint64_t)viewId {
   FlutterViewController* controller = [_viewControllers objectForKey:@(viewId)];
   NSAssert(controller == nil || controller.viewId == viewId,
            @"The stored controller has unexpected view ID.");
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterEngineTest.mm b/shell/platform/darwin/macos/framework/Source/FlutterEngineTest.mm
index a0101678b58a4..36c7d745cdf41 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterEngineTest.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterEngineTest.mm
@@ -647,7 +647,7 @@ - (nonnull NSView*)createWithViewIdentifier:(int64_t)viewId arguments:(nullable
   @autoreleasepool {
     // Create FVC1.
     viewController1 = [[FlutterViewController alloc] initWithProject:project];
-    EXPECT_EQ(viewController1.viewId, 0ll);
+    EXPECT_EQ(viewController1.viewId, 0ull);
 
     engine = viewController1.engine;
     engine.viewController = nil;
@@ -664,7 +664,7 @@ - (nonnull NSView*)createWithViewIdentifier:(int64_t)viewId arguments:(nullable
 
   engine.viewController = viewController1;
   EXPECT_EQ(engine.viewController, viewController1);
-  EXPECT_EQ(viewController1.viewId, 0ll);
+  EXPECT_EQ(viewController1.viewId, 0ull);
 }
 
 TEST_F(FlutterEngineTest, ManageControllersIfInitiatedByEngine) {
@@ -678,7 +678,7 @@ - (nonnull NSView*)createWithViewIdentifier:(int64_t)viewId arguments:(nullable
 
   @autoreleasepool {
     viewController1 = [[FlutterViewController alloc] initWithEngine:engine nibName:nil bundle:nil];
-    EXPECT_EQ(viewController1.viewId, 0ll);
+    EXPECT_EQ(viewController1.viewId, 0ull);
     EXPECT_EQ(engine.viewController, viewController1);
 
     engine.viewController = nil;
@@ -686,7 +686,7 @@ - (nonnull NSView*)createWithViewIdentifier:(int64_t)viewId arguments:(nullable
     FlutterViewController* viewController2 = [[FlutterViewController alloc] initWithEngine:engine
                                                                                    nibName:nil
                                                                                     bundle:nil];
-    EXPECT_EQ(viewController2.viewId, 0ll);
+    EXPECT_EQ(viewController2.viewId, 0ull);
     EXPECT_EQ(engine.viewController, viewController2);
   }
   // FVC2 is deallocated but FVC1 is retained.
@@ -695,7 +695,7 @@ - (nonnull NSView*)createWithViewIdentifier:(int64_t)viewId arguments:(nullable
 
   engine.viewController = viewController1;
   EXPECT_EQ(engine.viewController, viewController1);
-  EXPECT_EQ(viewController1.viewId, 0ll);
+  EXPECT_EQ(viewController1.viewId, 0ull);
 }
 
 TEST_F(FlutterEngineTest, HandlesTerminationRequest) {
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h b/shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h
index 892ee690b42b5..9b705a030690b 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterEngine_Internal.h
@@ -133,7 +133,7 @@ typedef NS_ENUM(NSInteger, FlutterAppExitResponse) {
 /**
  * The |FlutterViewController| associated with the given view ID, if any.
  */
-- (nullable FlutterViewController*)viewControllerForId:(int64_t)viewId;
+- (nullable FlutterViewController*)viewControllerForId:(uint64_t)viewId;
 
 /**
  * Informs the engine that the specified view controller's window metrics have changed.
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterPlatformNodeDelegateMacTest.mm b/shell/platform/darwin/macos/framework/Source/FlutterPlatformNodeDelegateMacTest.mm
index f05210012ed3c..d7c12689fe729 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterPlatformNodeDelegateMacTest.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterPlatformNodeDelegateMacTest.mm
@@ -192,7 +192,7 @@
 
   // Set up embedder API mock.
   FlutterSemanticsAction called_action;
-  int64_t called_id;
+  uint64_t called_id;
 
   engine.embedderAPI.DispatchSemanticsAction = MOCK_ENGINE_PROC(
       DispatchSemanticsAction,
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterRenderer.h b/shell/platform/darwin/macos/framework/Source/FlutterRenderer.h
index 47e280296ae80..483a858032bc8 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterRenderer.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterRenderer.h
@@ -38,12 +38,12 @@
 /**
  * Called by the engine when the given view's buffers should be swapped.
  */
-- (BOOL)present:(int64_t)viewId texture:(nonnull const FlutterMetalTexture*)texture;
+- (BOOL)present:(uint64_t)viewId texture:(nonnull const FlutterMetalTexture*)texture;
 
 /**
  * Creates a Metal texture for the given view with the given size.
  */
-- (FlutterMetalTexture)createTextureForView:(int64_t)viewId size:(CGSize)size;
+- (FlutterMetalTexture)createTextureForView:(uint64_t)viewId size:(CGSize)size;
 
 /**
  * Populates the texture registry with the provided metalTexture.
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterRenderer.mm b/shell/platform/darwin/macos/framework/Source/FlutterRenderer.mm
index fcee537f3b404..d7d2c2fc7d6ac 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterRenderer.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterRenderer.mm
@@ -17,7 +17,7 @@ static FlutterMetalTexture OnGetNextDrawableForDefaultView(FlutterEngine* engine
   // TODO(dkwingsmt): This callback only supports single-view, therefore it only
   // operates on the default view. To support multi-view, we need a new callback
   // that also receives a view ID, or pass the ID via FlutterFrameInfo.
-  int64_t viewId = kFlutterDefaultViewId;
+  uint64_t viewId = kFlutterDefaultViewId;
   CGSize size = CGSizeMake(frameInfo->size.width, frameInfo->size.height);
   return [engine.renderer createTextureForView:viewId size:size];
 }
@@ -27,7 +27,7 @@ static bool OnPresentDrawableOfDefaultView(FlutterEngine* engine,
   // TODO(dkwingsmt): This callback only supports single-view, therefore it only
   // operates on the default view. To support multi-view, we need a new callback
   // that also receives a view ID.
-  int64_t viewId = kFlutterDefaultViewId;
+  uint64_t viewId = kFlutterDefaultViewId;
   return [engine.renderer present:viewId texture:texture];
 }
 
@@ -88,7 +88,7 @@ - (FlutterRendererConfig)createRendererConfig {
 
 #pragma mark - Embedder callback implementations.
 
-- (FlutterMetalTexture)createTextureForView:(int64_t)viewId size:(CGSize)size {
+- (FlutterMetalTexture)createTextureForView:(uint64_t)viewId size:(CGSize)size {
   FlutterView* view = [_viewProvider viewForId:viewId];
   NSAssert(view != nil, @"Can't create texture on a non-existent view 0x%llx.", viewId);
   if (view == nil) {
@@ -98,7 +98,7 @@ - (FlutterMetalTexture)createTextureForView:(int64_t)viewId size:(CGSize)size {
   return [view.surfaceManager surfaceForSize:size].asFlutterMetalTexture;
 }
 
-- (BOOL)present:(int64_t)viewId texture:(const FlutterMetalTexture*)texture {
+- (BOOL)present:(uint64_t)viewId texture:(const FlutterMetalTexture*)texture {
   FlutterView* view = [_viewProvider viewForId:viewId];
   if (view == nil) {
     return NO;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm b/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
index 7430086debd4e..48e725542c40d 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm
@@ -454,7 +454,7 @@ - (void)setBackgroundColor:(NSColor*)color {
   [_flutterView setBackgroundColor:_backgroundColor];
 }
 
-- (int64_t)viewId {
+- (uint64_t)viewId {
   NSAssert([self attached], @"This view controller is not attched.");
   return _viewId;
 }
@@ -483,7 +483,7 @@ - (void)notifySemanticsEnabledChanged {
   return _bridge;
 }
 
-- (void)attachToEngine:(nonnull FlutterEngine*)engine withId:(int64_t)viewId {
+- (void)attachToEngine:(nonnull FlutterEngine*)engine withId:(uint64_t)viewId {
   NSAssert(_engine == nil, @"Already attached to an engine %@.", _engine);
   _engine = engine;
   _viewId = viewId;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterViewController_Internal.h b/shell/platform/darwin/macos/framework/Source/FlutterViewController_Internal.h
index b4ef62fa3eb97..1281b60694765 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterViewController_Internal.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterViewController_Internal.h
@@ -33,7 +33,7 @@
  *
  * This method is called by FlutterEngine.
  */
-- (void)attachToEngine:(nonnull FlutterEngine*)engine withId:(int64_t)viewId;
+- (void)attachToEngine:(nonnull FlutterEngine*)engine withId:(uint64_t)viewId;
 
 /**
  * Reset the `engine` and `id` of this controller.
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterViewEngineProvider.mm b/shell/platform/darwin/macos/framework/Source/FlutterViewEngineProvider.mm
index a4915a0cb88e1..95c3aa53e0ee5 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterViewEngineProvider.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterViewEngineProvider.mm
@@ -22,7 +22,7 @@ - (instancetype)initWithEngine:(FlutterEngine*)engine {
   return self;
 }
 
-- (nullable FlutterView*)viewForId:(int64_t)viewId {
+- (nullable FlutterView*)viewForId:(uint64_t)viewId {
   return [_engine viewControllerForId:viewId].flutterView;
 }
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterViewEngineProviderTest.mm b/shell/platform/darwin/macos/framework/Source/FlutterViewEngineProviderTest.mm
index 1e9dcdf11ab5d..86c94a70caa60 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterViewEngineProviderTest.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterViewEngineProviderTest.mm
@@ -25,7 +25,7 @@
   OCMStub([mockEngine viewControllerForId:0])
       .ignoringNonObjectArgs()
       .andDo(^(NSInvocation* invocation) {
-        int64_t viewId;
+        uint64_t viewId;
         [invocation getArgument:&viewId atIndex:2];
         if (viewId == 0 /* kFlutterDefaultViewId */) {
           if (mockFlutterViewController != nil) {
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterViewProvider.h b/shell/platform/darwin/macos/framework/Source/FlutterViewProvider.h
index e772573518650..9548b7afab1b8 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterViewProvider.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterViewProvider.h
@@ -4,7 +4,7 @@
 
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterView.h"
 
-extern const int64_t kFlutterDefaultViewId;
+extern const uint64_t kFlutterDefaultViewId;
 
 /**
  * An interface to query FlutterView.
@@ -20,6 +20,6 @@ extern const int64_t kFlutterDefaultViewId;
  *
  * Returns nil if the ID is invalid.
  */
-- (nullable FlutterView*)viewForId:(int64_t)id;
+- (nullable FlutterView*)viewForId:(uint64_t)id;
 
 @end