Introduce WebRange::isEmpty.

third_party/WebKit/Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 2811 matching lines @@
 
 void WebViewImpl::didChangeWindowResizerRect()
 {
     if (mainFrameImpl()->frameView())
         mainFrameImpl()->frameView()->windowResizerRectChanged();
 }
 
 bool WebViewImpl::getCompositionCharacterBounds(WebVector<WebRect>& bounds)
 {
     WebRange range = compositionRange();
-    if (range.isNull())
-        return false;
-
-    if (range.length() == 0)
+    if (range.isEmpty())
         return false;
 
     WebLocalFrame* frame = focusedFrame();
 
     // Only consider frames whose local root is the main frame. For other
     // local frames which have different local roots, the corresponding
     // WebFrameWidget will handle this task.
     if (frame->localRoot() != mainFrameImpl())
         return false;
 
@@ skipping 1745 matching lines @@
         return nullptr;
     return focusedFrame;
 }
 
 LocalFrame* WebViewImpl::focusedLocalFrameAvailableForIme() const
 {
     return m_imeAcceptEvents ? focusedLocalFrameInWidget() : nullptr;
 }
 
 } // namespace blink