Add support for sending generated character with key events.

shell/platform/android/io/flutter/embedding/engine/systemchannels/KeyEventChannel.java

@@ -10,6 +10,7 @@
 import java.util.HashMap;
 import java.util.Map;
 
+import android.view.KeyCharacterMap;
 import io.flutter.embedding.engine.dart.DartExecutor;
 import io.flutter.plugin.common.BasicMessageChannel;
 import io.flutter.plugin.common.JSONMessageCodec;
@@ -22,6 +23,8 @@ public class KeyEventChannel {
   @NonNull
   public final BasicMessageChannel<Object> channel;
 
+  private int mCombiningCharacter;
+
   public KeyEventChannel(@NonNull DartExecutor dartExecutor) {
     this.channel = new BasicMessageChannel<>(dartExecutor, "flutter/keyevent", JSONMessageCodec.INSTANCE);
   }
@@ -46,9 +49,32 @@ public void keyDown(@NonNull KeyEvent keyEvent) {
 
   private void encodeKeyEvent(@NonNull KeyEvent event, @NonNull Map<String, Object> message) {
     message.put("flags", event.getFlags());
-    message.put("codePoint", event.getUnicodeChar());
+    int codePoint = event.getUnicodeChar();
+    message.put("plainCodePoint", event.getUnicodeChar(0x0));
+    message.put("codePoint", codePoint);
     message.put("keyCode", event.getKeyCode());
     message.put("scanCode", event.getScanCode());
     message.put("metaState", event.getMetaState());
+    if (codePoint == 0) {
+      return;
+    }
+    if ((codePoint & KeyCharacterMap.COMBINING_ACCENT) != 0) {
+      // If a combining character was entered before, combine this one with that one.
+      int plainCodePoint = codePoint & KeyCharacterMap.COMBINING_ACCENT_MASK;
+      if (mCombiningCharacter != 0) {
+        mCombiningCharacter = KeyCharacterMap.getDeadChar(mCombiningCharacter, plainCodePoint);
+      } else {
+        mCombiningCharacter = plainCodePoint;
+      }
+    } else {
+      if (mCombiningCharacter != 0) {
+        int combinedChar = KeyCharacterMap.getDeadChar(mCombiningCharacter, codePoint);
+        if (combinedChar > 0) {
+          codePoint = combinedChar;
+        }
+        mCombiningCharacter = 0;
+      }
+      message.put("character", Character.toString((char) codePoint));
+    }
   }
 }

shell/platform/android/io/flutter/view/FlutterView.java

@@ -173,6 +173,7 @@ public void surfaceDestroyed(SurfaceHolder holder) {
         mImm = (InputMethodManager) getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
         mTextInputPlugin = new TextInputPlugin(this);
 
+
         setLocales(getResources().getConfiguration());
         sendUserPlatformSettingsToDart();
     }