Create base class for common functionality of Web{Local,Remote}Frame

third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp

 /*
  * Copyright (C) 2009, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2011 Apple 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.
@@ skipping 90 matching lines @@
 #include "web/WebPluginContainerImpl.h"
 #include "web/WebPluginLoadObserver.h"
 #include "web/WebViewImpl.h"
 #include "wtf/StringExtras.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/WTFString.h"
 #include <v8.h>
 
 namespace blink {
 
+namespace {
+
+Frame* toCoreFrame(WebFrame* frame)
+{
+    return frame ? frame->toImplBase()->frame() : nullptr;

[dcheng, 2015/11/23 09:00:17]

Most locations that convert a WebFrame to a Frame don't need to care about null.
This and RemoteFrameClientImpl are the only locations that need to handle this
detail.

One alternative I considered was making a sentinel placeholder for logically
null WebFrames. This would avoid the need for the null check, but at the cost of
overloading:
  explicit operator bool() so the sentinel value tests to false
  operator==(std::nullptr_t, WebFrame*)
  operator==(WebFrame*, std::nullptr_t) so the sentinel value is considered
equivalent to nullptr

In the end, this seemed too clever and easy to accidentally break in some way,
so I ended up just going with the simple way.

+}
+
+} // namespace
+
 FrameLoaderClientImpl::FrameLoaderClientImpl(WebLocalFrameImpl* frame)
     : m_webFrame(frame)
 {
 }
 
 PassOwnPtrWillBeRawPtr<FrameLoaderClientImpl> FrameLoaderClientImpl::create(WebLocalFrameImpl* frame)
 {
     return adoptPtrWillBeNoop(new FrameLoaderClientImpl(frame));
 }
 
@@ skipping 864 matching lines @@
 
 void FrameLoaderClientImpl::suddenTerminationDisablerChanged(bool present, SuddenTerminationDisablerType type)
 {
     if (m_webFrame->client()) {
         m_webFrame->client()->suddenTerminationDisablerChanged(
             present, static_cast<WebFrameClient::SuddenTerminationDisablerType>(type));
     }
 }
 
 } // namespace blink