Register clipboard image blob in the browser process to copy data less.

third_party/WebKit/public/platform/WebMockClipboard.h

Index: third_party/WebKit/public/platform/WebMockClipboard.h
diff --git a/third_party/WebKit/public/platform/WebMockClipboard.h b/third_party/WebKit/public/platform/WebMockClipboard.h
new file mode 100644
index 0000000000000000000000000000000000000000..f02e4aea81a951bea4331fa78f0fa84895944183
--- /dev/null
+++ b/third_party/WebKit/public/platform/WebMockClipboard.h
@@ -0,0 +1,20 @@
+// Copyright 2016 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.
+
+#ifndef WebMockClipboard_h
+#define WebMockClipboard_h
+
+#include "public/platform/WebClipboard.h"
+#include "public/platform/WebImage.h"
+
+namespace blink {
+
+class WebMockClipboard : public WebClipboard {

[dcheng, 2016/04/11 03:22:54]

I'm not particularly thrilled about adding this class, but it seems the most
straightforward:
1) Without it, I need to figure out the unit test plumbing for blobs.
2) Even with the unit test plumbing, a lot of things only want the raw pixels
anyway and will just end up decoding the png. So adding this interface
simplifies those tests.

+public:
+    virtual WebImage readRawImage(Buffer) { return WebImage(); }
+};
+
+} // namespace blink
+
+#endif