Destroy GLX windows when they are backgrounded

ui/gl/gl_surface_glx.h

Index: ui/gl/gl_surface_glx.h
diff --git a/ui/gl/gl_surface_glx.h b/ui/gl/gl_surface_glx.h
index 355b65d1c45e71a2b6ba1450cbaef9cbbad5b1a7..8e7bd1c0c784ff4a75ce61720f97998f5044c309 100644
--- a/ui/gl/gl_surface_glx.h
+++ b/ui/gl/gl_surface_glx.h
@@ -69,9 +69,41 @@ class GL_EXPORT NativeViewGLSurfaceGLX : public GLSurfaceGLX {
   NativeViewGLSurfaceGLX();
   virtual ~NativeViewGLSurfaceGLX();
 
-  gfx::AcceleratedWidget window_;
-
  private:
+  // The handle for the drawable to make current or swap.
+  gfx::AcceleratedWidget GetDrawableHandle() const;
+
+  // Window passed in at creation. Always valid.
+  gfx::AcceleratedWidget parent_window_;
+
+#if defined(TOOLKIT_GTK)
+  // Some NVIDIA drivers don't allow deleting GLX windows separately from their
+  // parent X windows. Work around this by creating a child X window to the
+  // window passed in to the constructor, creating the GLX window against the
+  // child window, and then destroying the child window to destroy the GLX
+  // window.
+  // http://crbug.com/145600
+  void CreateChildWindow();
+  void DestroyChildWindow();
+
+  // Destroy the child window when both the front and back buffers are
+  // deallocated.
+  virtual bool SetBackbufferAllocation(bool allocated) OVERRIDE;
+  virtual void SetFrontbufferAllocation(bool allocated) OVERRIDE;
+  void AdjustBufferAllocation();
+
+  // Child window which is used with GLX, and is discarded when it is
+  // backgrounded.
+  gfx::AcceleratedWidget child_window_;
+
+  // Dummy 1x1 window which is supplied to glXMakeCurrent when making
+  // the context current while its output surface is destroyed.
+  gfx::AcceleratedWidget dummy_window_;
+
+  bool backbuffer_allocated_;
+  bool frontbuffer_allocated_;
+#endif
+
   void* config_;
   gfx::Size size_;