This CL adds client.toDataURL which gets the contents...

core/cross/client.h

 /*
  * Copyright 2009, 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.
@@ skipping 377 matching lines @@
 
   // Stops the timer for the code range identified by key.
   void ProfileStop(const std::string& key);
 
   // Resets the profiler, clearing out all data.
   void ProfileReset();
 
   // Dumps all profiler state to a string.
   String ProfileToString();
 
-  // Saves a png screenshot of the display buffer.
-  // Returns true on success and false on failure.
-  bool SaveScreen(const String& file_name);
+  // Reutrns a data: URL of the client area in png format.
+  String ToDataURL();
 
   // This class is intended to be used on the stack, such that the variable gets
   // incremented on scope entry and decremented on scope exit.  It's currently
   // used in WindowProc to determine if we're reentrant or not, but may be
   // needed on other platforms as well.
   class ScopedIncrement {
    public:
     explicit ScopedIncrement(Client *client) {
       DCHECK(client);
       client_ = client;
@@ skipping 86 matching lines @@
   Id id_;
 
   int calls_;  // Used to check reentrancy along with ScopedIncrement.
 
   DISALLOW_COPY_AND_ASSIGN(Client);
 };  // Client
 
 }  // namespace o3d
 
 #endif  // O3D_CORE_CROSS_CLIENT_H_