updating Input field value by script should reset IME composition.

third_party/WebKit/Source/web/ChromeClientImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 1061 matching lines @@
   if (WebViewClient* client = web_view_->Client())
     client->DraggableRegionsChanged();
 }
 
 void ChromeClientImpl::DidAssociateFormControlsAfterLoad(LocalFrame* frame) {
   WebLocalFrameImpl* webframe = WebLocalFrameImpl::FromFrame(frame);
   if (webframe->AutofillClient())
     webframe->AutofillClient()->DidAssociateFormControlsDynamically();
 }
 
+void ChromeClientImpl::DidCancelCompositionOnSelectionChange() {
+  if (web_view_->Client())
+    web_view_->Client()->DidCancelCompositionOnSelectionChange();
+}
+
 void ChromeClientImpl::ShowVirtualKeyboardOnElementFocus(LocalFrame& frame) {
   WebLocalFrameImpl::FromFrame(frame.LocalFrameRoot())
       ->FrameWidget()
       ->Client()
       ->ShowVirtualKeyboardOnElementFocus();
 }
 
 void ChromeClientImpl::ShowUnhandledTapUIIfNeeded(
     IntPoint tapped_position_in_viewport,
     Node* tapped_node,
@@ skipping 141 matching lines @@
   if (RuntimeEnabledFeatures::presentationEnabled())
     PresentationController::ProvideTo(frame, client->PresentationClient());
   if (RuntimeEnabledFeatures::audioOutputDevicesEnabled()) {
     ProvideAudioOutputDeviceClientTo(frame,
                                      new AudioOutputDeviceClientImpl(frame));
   }
   InstalledAppController::ProvideTo(frame, client->GetRelatedAppsFetcher());
 }
 
 }  // namespace blink