Command to mark surface inactive, so gpu process can release resources.

content/common/gpu/image_transport_surface_linux.h

Index: content/common/gpu/image_transport_surface_linux.h
diff --git a/content/common/gpu/image_transport_surface_linux.h b/content/common/gpu/image_transport_surface_linux.h
index b146ab0547ab3e11eee385f07e97d0b73f0253b1..71608d5c7fb7a6c14681727e20a05ea817dd5669 100644
--- a/content/common/gpu/image_transport_surface_linux.h
+++ b/content/common/gpu/image_transport_surface_linux.h
@@ -38,6 +38,7 @@ class ImageTransportSurface {
       uint64 surface_id, TransportDIB::Handle surface_handle) = 0;
   virtual void OnBuffersSwappedACK() = 0;
   virtual void OnResize(gfx::Size size) = 0;
+  virtual void OnSurfaceVisible(bool visible) = 0;
 
   // Creates the appropriate surface depending on the GL implementation.
   static scoped_refptr<gfx::GLSurface>
@@ -89,6 +90,9 @@ class ImageTransportHelper : public IPC::Channel::Listener {
   // Backbuffer resize callback.
   void Resize(gfx::Size size);
 
+  // Backbuffer visibility changed callback
+  void SurfaceVisible(bool visible);
+
   // Weak pointers that to objects that outlive this helper.
   ImageTransportSurface* surface_;
   GpuChannelManager* manager_;