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

ui/gl/gl_context_osmesa.cc

Index: ui/gl/gl_context_osmesa.cc
diff --git a/ui/gl/gl_context_osmesa.cc b/ui/gl/gl_context_osmesa.cc
index a279177011f7e85c428c8bc4e02088cf9b1292f2..8c400296cdf1faaf4137342304a41907e39c0f7d 100644
--- a/ui/gl/gl_context_osmesa.cc
+++ b/ui/gl/gl_context_osmesa.cc
@@ -14,7 +14,7 @@
 namespace gfx {
 
 GLContextOSMesa::GLContextOSMesa(GLShareGroup* share_group)
-    : GLContext(share_group),
+    : GLContextReal(share_group),
       context_(NULL) {
 }
 
@@ -65,7 +65,7 @@ bool GLContextOSMesa::MakeCurrent(GLSurface* surface) {
   // Row 0 is at the top.
   OSMesaPixelStore(OSMESA_Y_UP, 0);
 
-  SetCurrent(this, surface);
+  SetCurrent(surface);
   if (!InitializeExtensionBindings()) {
     ReleaseCurrent(surface);
     return false;
@@ -84,7 +84,7 @@ void GLContextOSMesa::ReleaseCurrent(GLSurface* surface) {
   if (!IsCurrent(surface))
     return;
 
-  SetCurrent(NULL, NULL);
+  SetCurrent(NULL);
   OSMesaMakeCurrent(NULL, NULL, GL_UNSIGNED_BYTE, 0, 0);
 }
 
@@ -97,7 +97,7 @@ bool GLContextOSMesa::IsCurrent(GLSurface* surface) {
   // If our context is current then our notion of which GLContext is
   // current must be correct. On the other hand, third-party code
   // using OpenGL might change the current context.
-  DCHECK(!native_context_is_current || (GetCurrent() == this));
+  DCHECK(!native_context_is_current || (GetRealCurrent() == this));
 
   if (!native_context_is_current)
     return false;