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 fe8ada21e7d6a15deb2fceb2a9fffbcbe0c14d87..cb32ffc40296c9bb62db0b0a4fa18d37df4b702a 100644
--- a/ui/gl/gl_context.h
+++ b/ui/gl/gl_context.h
@@ -88,8 +88,12 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
 
   static bool LosesAllContextsOnContextLost();
 
+  // Returns the last GLContext made current, virtual or real.
   static GLContext* GetCurrent();
 
+  // Returns the last real GLContext made current.
+  static GLContext* GetRealCurrent();
+
   virtual bool WasAllocatedUsingRobustnessExtension();
 
   // Use this context for virtualization.
@@ -114,6 +118,8 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   // current.
   bool InitializeExtensionBindings();
 
+  virtual bool IsVirtualContext();
+
  private:
   friend class base::RefCounted<GLContext>;