Revert "Reland "Hardware Keyboard: Android" (#33567)" (#33589)

This reverts commit ea9c2ec.

ci/licenses_golden/licenses_flutter

@@ -1313,10 +1313,7 @@ FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/Flutt
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/FlutterTextureView.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/FlutterView.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/KeyChannelResponder.java
-FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/KeyData.java
-FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/KeyEmbedderResponder.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/KeyboardManager.java
-FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/KeyboardMap.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/MotionEventTracker.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/RenderMode.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/SplashScreen.java

lib/ui/key.dart

@@ -146,7 +146,7 @@ class KeyData {
 
   String? _escapeCharacter() {
     if (character == null) {
-      return '<none>';
+      return character ?? '<none>';
     }
     switch (character!) {
       case '\n':

lib/ui/window/key_data.h

@@ -28,9 +28,6 @@ enum class KeyEventType : int64_t {
 // a different way in KeyDataPacket.
 //
 // This structure is unpacked by hooks.dart.
-//
-// Changes to this struct must also be made to
-// io/flutter/embedding/android/KeyData.java.
 struct alignas(8) KeyData {
   // Timestamp in microseconds from an arbitrary and consistent start point
   uint64_t timestamp;

lib/ui/window/key_data_packet.h

@@ -14,9 +14,6 @@
 namespace flutter {
 
 // A byte stream representing a key event, to be sent to the framework.
-//
-// Changes to the marshalling format here must also be made to
-// io/flutter/embedding/android/KeyData.java.
 class KeyDataPacket {
  public:
   // Build the key data packet by providing information.

shell/platform/android/BUILD.gn

@@ -185,10 +185,7 @@ android_java_sources = [
   "io/flutter/embedding/android/FlutterTextureView.java",
   "io/flutter/embedding/android/FlutterView.java",
   "io/flutter/embedding/android/KeyChannelResponder.java",
-  "io/flutter/embedding/android/KeyData.java",
-  "io/flutter/embedding/android/KeyEmbedderResponder.java",
   "io/flutter/embedding/android/KeyboardManager.java",
-  "io/flutter/embedding/android/KeyboardMap.java",
   "io/flutter/embedding/android/MotionEventTracker.java",
   "io/flutter/embedding/android/RenderMode.java",
   "io/flutter/embedding/android/SplashScreen.java",

shell/platform/android/io/flutter/embedding/android/KeyChannelResponder.java

@@ -4,6 +4,7 @@
 
 package io.flutter.embedding.android;
 
+import android.view.KeyCharacterMap;
 import android.view.KeyEvent;
 import androidx.annotation.NonNull;
 import io.flutter.embedding.engine.systemchannels.KeyEventChannel;
@@ -18,15 +19,66 @@ public class KeyChannelResponder implements KeyboardManager.Responder {
   private static final String TAG = "KeyChannelResponder";
 
   @NonNull private final KeyEventChannel keyEventChannel;
-
-  @NonNull
-  private final KeyboardManager.CharacterCombiner characterCombiner =
-      new KeyboardManager.CharacterCombiner();
+  private int combiningCharacter;
 
   public KeyChannelResponder(@NonNull KeyEventChannel keyEventChannel) {
     this.keyEventChannel = keyEventChannel;
   }
 
+  /**
+   * Applies the given Unicode character in {@code newCharacterCodePoint} to a previously entered
+   * Unicode combining character and returns the combination of these characters if a combination
+   * exists.
+   *
+   * <p>This method mutates {@link #combiningCharacter} over time to combine characters.
+   *
+   * <p>One of the following things happens in this method:
+   *
+   * <ul>
+   *   <li>If no previous {@link #combiningCharacter} exists and the {@code newCharacterCodePoint}
+   *       is not a combining character, then {@code newCharacterCodePoint} is returned.
+   *   <li>If no previous {@link #combiningCharacter} exists and the {@code newCharacterCodePoint}
+   *       is a combining character, then {@code newCharacterCodePoint} is saved as the {@link
+   *       #combiningCharacter} and null is returned.
+   *   <li>If a previous {@link #combiningCharacter} exists and the {@code newCharacterCodePoint} is
+   *       also a combining character, then the {@code newCharacterCodePoint} is combined with the
+   *       existing {@link #combiningCharacter} and null is returned.
+   *   <li>If a previous {@link #combiningCharacter} exists and the {@code newCharacterCodePoint} is
+   *       not a combining character, then the {@link #combiningCharacter} is applied to the regular
+   *       {@code newCharacterCodePoint} and the resulting complex character is returned. The {@link
+   *       #combiningCharacter} is cleared.
+   * </ul>
+   *
+   * <p>The following reference explains the concept of a "combining character":
+   * https://en.wikipedia.org/wiki/Combining_character
+   */
+  Character applyCombiningCharacterToBaseCharacter(int newCharacterCodePoint) {
+    char complexCharacter = (char) newCharacterCodePoint;
+    boolean isNewCodePointACombiningCharacter =
+        (newCharacterCodePoint & KeyCharacterMap.COMBINING_ACCENT) != 0;
+    if (isNewCodePointACombiningCharacter) {
+      // If a combining character was entered before, combine this one with that one.
+      int plainCodePoint = newCharacterCodePoint & KeyCharacterMap.COMBINING_ACCENT_MASK;
+      if (combiningCharacter != 0) {
+        combiningCharacter = KeyCharacterMap.getDeadChar(combiningCharacter, plainCodePoint);
+      } else {
+        combiningCharacter = plainCodePoint;
+      }
+    } else {
+      // The new character is a regular character. Apply combiningCharacter to it, if
+      // it exists.
+      if (combiningCharacter != 0) {
+        int combinedChar = KeyCharacterMap.getDeadChar(combiningCharacter, newCharacterCodePoint);
+        if (combinedChar > 0) {
+          complexCharacter = (char) combinedChar;
+        }
+        combiningCharacter = 0;
+      }
+    }
+
+    return complexCharacter;
+  }
+
   @Override
   public void handleEvent(
       @NonNull KeyEvent keyEvent, @NonNull OnKeyEventHandledCallback onKeyEventHandledCallback) {
@@ -40,7 +92,7 @@ public void handleEvent(
     }
 
     final Character complexCharacter =
-        characterCombiner.applyCombiningCharacterToBaseCharacter(keyEvent.getUnicodeChar());
+        applyCombiningCharacterToBaseCharacter(keyEvent.getUnicodeChar());
     KeyEventChannel.FlutterKeyEvent flutterEvent =
         new KeyEventChannel.FlutterKeyEvent(keyEvent, complexCharacter);