Add stubs and glue for routing a request for an image from the clipboard.

ui/base/clipboard/clipboard_mac.mm

 // Copyright (c) 2011 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.
 
 #include "ui/base/clipboard/clipboard.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/file_path.h"
 #include "base/logging.h"
@@ skipping 204 matching lines @@
     UTF8ToUTF16([contents UTF8String],
                 [contents lengthOfBytesUsingEncoding:NSUTF8StringEncoding],
                 markup);
   }
 
   // TODO(avi): src_url?
   if (src_url)
     src_url->clear();
 }
 
+void Clipboard::ReadImage(Buffer buffer, std::string* data) const {
+  DCHECK_EQ(buffer, BUFFER_STANDARD);
+  if (!data) {
+    NOTREACHED();
+    return;
+  }
+}
+
 void Clipboard::ReadBookmark(string16* title, std::string* url) const {
   NSPasteboard* pb = GetPasteboard();
 
   if (title) {
     NSString* contents = [pb stringForType:kUTTypeURLName];
     UTF8ToUTF16([contents UTF8String],
                 [contents lengthOfBytesUsingEncoding:NSUTF8StringEncoding],
                 title);
   }
 
@@ skipping 89 matching lines @@
 }
 
 // static
 Clipboard::FormatType Clipboard::GetWebKitSmartPasteFormatType() {
   static const std::string type =
       base::SysNSStringToUTF8(kWebSmartPastePboardType);
   return type;
 }
 
 }  // namespace ui