Revert restartInput change off the M57 release branch.

third_party/WebKit/Source/core/editing/InputMethodController.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 1062 matching lines @@
   }
 
   document().updateStyleAndLayoutTree();
   if (hasEditableStyle(*element))
     return WebTextInputTypeContentEditable;
 
   return WebTextInputTypeNone;
 }
 
 void InputMethodController::willChangeFocus() {
-  finishComposingText(KeepSelection);
+  if (!finishComposingText(KeepSelection))
+    return;
+  frame().chromeClient().resetInputMethod();
 }
 
 DEFINE_TRACE(InputMethodController) {
   visitor->trace(m_frame);
   visitor->trace(m_compositionRange);
   SynchronousMutationObserver::trace(visitor);
 }
 
 }  // namespace blink