GPU: Keep track of the last real context and real surface made current.

ui/gl/gl_context.h

Index: ui/gl/gl_context.h
diff --git a/ui/gl/gl_context.h b/ui/gl/gl_context.h
index dc65f64a8ae6baad9b6990ef104a46ba445b99d4..e396ca0cc2258e2c515f56b130b4a069cbc147cb 100644
--- a/ui/gl/gl_context.h
+++ b/ui/gl/gl_context.h
@@ -88,6 +88,7 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
 
   static bool LosesAllContextsOnContextLost();
 
+  // Returns the last GLContext made current, virtual or real.
   static GLContext* GetCurrent();
 
   virtual bool WasAllocatedUsingRobustnessExtension();
@@ -114,9 +115,17 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   // current.
   bool InitializeExtensionBindings();
 
+  virtual bool IsVirtualContext();
+
+  // Returns the last real (non-virtual) GLContext made current.
+  static GLContext* GetRealCurrent();
+
  private:
   friend class base::RefCounted<GLContext>;
 
+  // For GetRealCurrent.
+  friend class VirtualGLApi;
+
   scoped_refptr<GLShareGroup> share_group_;
   scoped_ptr<VirtualGLApi> virtual_gl_api_;
   scoped_ptr<GLStateRestorer> state_restorer_;