Refactor how surfaces are acquired for GPU compositing.

chrome/browser/gpu_process_host_ui_shim.h

Index: chrome/browser/gpu_process_host_ui_shim.h
diff --git a/chrome/browser/gpu_process_host_ui_shim.h b/chrome/browser/gpu_process_host_ui_shim.h
index a47e2e6da1b564c252b5d67cc8bcfb09c776fc8e..ce706e88ecb93149ce1d5eb9deeaa4e54fb00de0 100644
--- a/chrome/browser/gpu_process_host_ui_shim.h
+++ b/chrome/browser/gpu_process_host_ui_shim.h
@@ -11,10 +11,12 @@
 // portion of this class, the GpuProcessHost, is responsible for
 // shuttling messages between the browser and GPU processes.
 
+#include <map>
 #include <queue>
 
 #include "base/callback.h"
 #include "base/linked_ptr.h"
+#include "base/ref_counted.h"
 #include "base/scoped_ptr.h"
 #include "base/singleton.h"
 #include "base/values.h"
@@ -40,6 +42,8 @@ struct ChannelHandle;
 class Message;
 }
 
+class RenderWidgetHostView;
+
 class GpuProcessHostUIShim : public IPC::Channel::Sender,
                              public IPC::Channel::Listener,
                              public base::NonThreadSafe {
@@ -173,6 +177,25 @@ class GpuProcessHostUIShim : public IPC::Channel::Sender,
   std::queue<linked_ptr<CreateCommandBufferCallback> >
       create_command_buffer_requests_;
 
+  typedef std::pair<int32 /* renderer_id */,
+                    int32 /* render_view_id */> ViewID;
+
+  // Encapsulates surfaces that we acquire when creating view command buffers.
+  // We assume that a render view has at most 1 such surface associated
+  // with it.
+  class ViewSurface : public base::RefCounted<ViewSurface> {
+   public:
+    explicit ViewSurface(ViewID view_id);
+    ~ViewSurface();
+    gfx::PluginWindowHandle surface() { return surface_; }
+   private:
+    RenderWidgetHostView* GetRenderWidgetHostView();
+    ViewID view_id_;
+    gfx::PluginWindowHandle surface_;
+  };
+
+  std::map<ViewID, scoped_refptr<ViewSurface> > acquired_surfaces_;
+
   bool initialized_;
   bool initialized_successfully_;