[Clank IME] Make keyCode detection sensitive to autocomplete=on|off.

content/public/android/java/src/org/chromium/content/browser/input/ImeAdapter.java

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.content.browser.input;
 
 import android.os.Handler;
 import android.os.ResultReceiver;
 import android.os.SystemClock;
 import android.text.Editable;
@@ skipping 363 matching lines @@
                 return androidKeyEventForCharacter(newtext.charAt(0));
             } else {
                 return null;
             }
         }
 
         // The content has grown in length: assume the last character is the key that caused it.
         if (newtext.length() > oldtext.length() && newtext.startsWith(oldtext))
             return androidKeyEventForCharacter(newtext.charAt(newtext.length() - 1));
 
-        // The content has shrunk in length: assume that backspace was pressed.
-        if (oldtext.length() > newtext.length() && oldtext.startsWith(newtext))
+        // The content has shrunk in length: assume that backspace was pressed, unless a deleted
+        // character (last element of |oldtext|) has no corresponding key event. This prevents
+        // Japanese IME compositions from being cleared on backspace (see crbug.com/422685).
+        if (oldtext.length() > newtext.length() && oldtext.startsWith(newtext)
+                && androidKeyEventForCharacter(oldtext.charAt(oldtext.length() - 1)) != null)

[bcwhite, 2015/01/09 22:52:44]

Have you tested this as working?  A potential problem is that when looking for
the event for a character, it will find something if Android knows of a
*sequence* of key presses that will create that character.

If it works, great, but test it with a number of different characters.

Also, please write a test for this.

             return new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DEL);
 
         // The content is unchanged or has undergone a complex change (i.e. not a simple tail
         // modification) so return an unknown key-code.
         return null;
     }
 
     void sendKeyEventWithKeyCode(int keyCode, int flags) {
         long eventTime = SystemClock.uptimeMillis();
         mLastSyntheticKeyCode = keyCode;
@@ skipping 314 matching lines @@
     private native void nativeDeleteSurroundingText(long nativeImeAdapterAndroid,
             int before, int after);
 
     private native void nativeUnselect(long nativeImeAdapterAndroid);
     private native void nativeSelectAll(long nativeImeAdapterAndroid);
     private native void nativeCut(long nativeImeAdapterAndroid);
     private native void nativeCopy(long nativeImeAdapterAndroid);
     private native void nativePaste(long nativeImeAdapterAndroid);
     private native void nativeResetImeAdapter(long nativeImeAdapterAndroid);
 }