Rewrite clipboard write IPC handling to be easier to understand.

ui/base/clipboard/scoped_clipboard_writer.h

 // Copyright (c) 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.
 
 // This file declares the ScopedClipboardWriter class, a wrapper around
 // the Clipboard class which simplifies writing data to the system clipboard.
 // Upon deletion the class atomically writes all data to the clipboard,
 // avoiding any potential race condition with other processes that are also
 // writing to the system clipboard.
 
 #ifndef UI_BASE_CLIPBOARD_SCOPED_CLIPBOARD_WRITER_H_
 #define UI_BASE_CLIPBOARD_SCOPED_CLIPBOARD_WRITER_H_
 
 #include <string>
 
 #include "base/strings/string16.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/base/clipboard/clipboard.h"
 #include "ui/base/ui_base_export.h"
 
 class Pickle;
 
 namespace ui {
 
 // This class is a wrapper for |Clipboard| that handles packing data
 // into a Clipboard::ObjectMap.
 class UI_BASE_EXPORT ScopedClipboardWriter {
@@ skipping 27 matching lines @@
   void WriteHyperlink(const base::string16& anchor_text,
                       const std::string& url);
 
   // Used by WebKit to determine whether WebKit wrote the clipboard last
   void WriteWebSmartPaste();
 
   // Adds arbitrary pickled data to clipboard.
   void WritePickledData(const Pickle& pickle,
                         const Clipboard::FormatType& format);
 
+  void WriteImage(const SkBitmap& bitmap);
+
   // Removes all objects that would be written to the clipboard.
   void Reset();
 
- protected:
+ private:
   // Converts |text| to UTF-8 and adds it to the clipboard.  If it's a URL, we
   // also notify the clipboard of that fact.
   void WriteTextOrURL(const base::string16& text, bool is_url);
 
   // We accumulate the data passed to the various targets in the |objects_|
   // vector, and pass it to Clipboard::WriteObjects() during object destruction.
   Clipboard::ObjectMap objects_;
   const ClipboardType type_;
 
+  SkBitmap bitmap_;
+
   // We keep around the UTF-8 text of the URL in order to pass it to
   // Clipboard::DidWriteURL().
   std::string url_text_;
 
- private:
   DISALLOW_COPY_AND_ASSIGN(ScopedClipboardWriter);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_CLIPBOARD_SCOPED_CLIPBOARD_WRITER_H_