Temporary Fixes until PRs are Merged

Contains code from the following PRs:

flutter#2761
flutter#2755

Author: Juan Alvarez

packages/image_picker/image_picker/ios/Classes/FLTImagePickerPlugin.h

@@ -7,7 +7,6 @@
 @interface FLTImagePickerPlugin : NSObject <FlutterPlugin>
 
 // For testing only.
-- (instancetype)initWithViewController:(UIViewController *)viewController;
 - (UIImagePickerController *)getImagePickerController;
 
 @end

packages/image_picker/image_picker/ios/Classes/FLTImagePickerPlugin.m

@@ -25,33 +25,31 @@ @interface FLTImagePickerPlugin () <UINavigationControllerDelegate, UIImagePicke
 @implementation FLTImagePickerPlugin {
   NSDictionary *_arguments;
   UIImagePickerController *_imagePickerController;
-  UIViewController *_viewController;
   UIImagePickerControllerCameraDevice _device;
 }
 
 + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
   FlutterMethodChannel *channel =
       [FlutterMethodChannel methodChannelWithName:@"plugins.flutter.io/image_picker"
                                   binaryMessenger:[registrar messenger]];
-  UIViewController *viewController =
-      [UIApplication sharedApplication].delegate.window.rootViewController;
   FLTImagePickerPlugin *instance =
-      [[FLTImagePickerPlugin alloc] initWithViewController:viewController];
+      [[FLTImagePickerPlugin alloc] init];
   [registrar addMethodCallDelegate:instance channel:channel];
 }
 
-- (instancetype)initWithViewController:(UIViewController *)viewController {
-  self = [super init];
-  if (self) {
-    _viewController = viewController;
-  }
-  return self;
-}
-
 - (UIImagePickerController *)getImagePickerController {
   return _imagePickerController;
 }
 
+- (UIViewController *)viewController {
+    UIViewController *topController = UIApplication.sharedApplication.keyWindow.rootViewController;
+    while (topController.presentedViewController) {
+        topController = topController.presentedViewController;
+    }
+    
+    return topController;
+}
+
 - (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
   if (self.result) {
     self.result([FlutterError errorWithCode:@"multiple_request"
@@ -136,7 +134,7 @@ - (void)showCamera {
       [UIImagePickerController isCameraDeviceAvailable:_device]) {
     _imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
     _imagePickerController.cameraDevice = _device;
-    [_viewController presentViewController:_imagePickerController animated:YES completion:nil];
+    [[self viewController] presentViewController:_imagePickerController animated:YES completion:nil];
   } else {
     [[[UIAlertView alloc] initWithTitle:@"Error"
                                 message:@"Camera not available."
@@ -241,7 +239,7 @@ - (void)errorNoPhotoAccess:(PHAuthorizationStatus)status {
 - (void)showPhotoLibrary {
   // No need to check if SourceType is available. It always is.
   _imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
-  [_viewController presentViewController:_imagePickerController animated:YES completion:nil];
+  [[self viewController] presentViewController:_imagePickerController animated:YES completion:nil];
 }
 
 - (void)imagePickerController:(UIImagePickerController *)picker

packages/image_picker/image_picker/ios/Tests/ImagePickerPluginTests.m

@@ -23,7 +23,7 @@ - (void)testPluginPickImageDeviceBack {
     return;
   }
   FLTImagePickerPlugin *plugin =
-      [[FLTImagePickerPlugin alloc] initWithViewController:[UIViewController new]];
+      [[FLTImagePickerPlugin alloc] init];
   FlutterMethodCall *call =
       [FlutterMethodCall methodCallWithMethodName:@"pickImage"
                                         arguments:@{@"source" : @(0), @"cameraDevice" : @(0)}];
@@ -39,7 +39,7 @@ - (void)testPluginPickImageDeviceFront {
     return;
   }
   FLTImagePickerPlugin *plugin =
-      [[FLTImagePickerPlugin alloc] initWithViewController:[UIViewController new]];
+      [[FLTImagePickerPlugin alloc] init];
   FlutterMethodCall *call =
       [FlutterMethodCall methodCallWithMethodName:@"pickImage"
                                         arguments:@{@"source" : @(0), @"cameraDevice" : @(1)}];
@@ -55,7 +55,7 @@ - (void)testPluginPickVideoDeviceBack {
     return;
   }
   FLTImagePickerPlugin *plugin =
-      [[FLTImagePickerPlugin alloc] initWithViewController:[UIViewController new]];
+      [[FLTImagePickerPlugin alloc] init];
   FlutterMethodCall *call =
       [FlutterMethodCall methodCallWithMethodName:@"pickVideo"
                                         arguments:@{@"source" : @(0), @"cameraDevice" : @(0)}];
@@ -71,7 +71,7 @@ - (void)testPluginPickVideoDeviceFront {
     return;
   }
   FLTImagePickerPlugin *plugin =
-      [[FLTImagePickerPlugin alloc] initWithViewController:[UIViewController new]];
+      [[FLTImagePickerPlugin alloc] init];
   FlutterMethodCall *call =
       [FlutterMethodCall methodCallWithMethodName:@"pickVideo"
                                         arguments:@{@"source" : @(0), @"cameraDevice" : @(1)}];
@@ -85,7 +85,7 @@ - (void)testPluginPickVideoDeviceFront {
 #pragma mark - Test video duration
 - (void)testPickingVideoWithDuration {
   FLTImagePickerPlugin *plugin =
-      [[FLTImagePickerPlugin alloc] initWithViewController:[UIViewController new]];
+      [[FLTImagePickerPlugin alloc] init];
   FlutterMethodCall *call = [FlutterMethodCall
       methodCallWithMethodName:@"pickVideo"
                      arguments:@{@"source" : @(0), @"cameraDevice" : @(0), @"maxDuration" : @95}];
@@ -97,7 +97,7 @@ - (void)testPickingVideoWithDuration {
 
 - (void)testPluginPickImageSelectMultipleTimes {
   FLTImagePickerPlugin *plugin =
-      [[FLTImagePickerPlugin alloc] initWithViewController:[UIViewController new]];
+      [[FLTImagePickerPlugin alloc] init];
   FlutterMethodCall *call =
       [FlutterMethodCall methodCallWithMethodName:@"pickImage"
                                         arguments:@{@"source" : @(0), @"cameraDevice" : @(0)}];