Inform webkit when PPAPI plugin contents are opaque.

webkit/plugins/ppapi/plugin_delegate.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.
 
 #ifndef WEBKIT_PLUGINS_PPAPI_PLUGIN_DELEGATE_H_
 #define WEBKIT_PLUGINS_PPAPI_PLUGIN_DELEGATE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 153 matching lines @@
    public:
     virtual ~PlatformContext3D() {}
 
     // Initialize the context.
     virtual bool Init(const int32* attrib_list) = 0;
 
     // If the plugin instance is backed by an OpenGL, return its ID in the
     // compositors namespace. Otherwise return 0. Returns 0 by default.
     virtual unsigned GetBackingTextureId() = 0;
 
+    // Returns true if the backing texture is always opaque.
+    virtual bool IsOpaque() = 0;
+
     // This call will return the address of the command buffer for this context
     // that is constructed in Initialize() and is valid until this context is
     // destroyed.
     virtual ::gpu::CommandBuffer* GetCommandBuffer() = 0;
 
     // If the command buffer is routed in the GPU channel, return the route id.
     // Otherwise return 0.
     virtual int GetCommandBufferRouteId() = 0;
 
     // Set an optional callback that will be invoked when the context is lost
@@ skipping 395 matching lines @@
                                const EnumerateDevicesCallback& callback) = 0;
   // Create a ClipboardClient for writing to the clipboard. The caller will own
   // the pointer to this.
   virtual webkit_glue::ClipboardClient* CreateClipboardClient() const = 0;
 };
 
 }  // namespace ppapi
 }  // namespace webkit
 
 #endif  // WEBKIT_PLUGINS_PPAPI_PLUGIN_DELEGATE_H_