Rebind EGL context to flush driver caches.

ui/gl/gl_gl_api_implementation.cc

Index: ui/gl/gl_gl_api_implementation.cc
diff --git a/ui/gl/gl_gl_api_implementation.cc b/ui/gl/gl_gl_api_implementation.cc
index 1d6fcb15d0a57485bd0c12bc5618f53d1d85ed04..1a0d7b78dbe935d6fc8a3a0e397d5a2d580db612 100644
--- a/ui/gl/gl_gl_api_implementation.cc
+++ b/ui/gl/gl_gl_api_implementation.cc
@@ -540,7 +540,7 @@ bool VirtualGLApi::MakeCurrent(GLContext* virtual_context, GLSurface* surface) {
     // MakeCurrent 'lite' path that avoids potentially expensive MakeCurrent()
     // calls if the GLSurface uses the same underlying surface or renders to
     // an FBO.
-    if (switched_contexts || !current_surface ||
+    if (switched_contexts || !current_surface || !surface ||

[ericrk, 2015/07/13 21:15:33]

This is a bit weird as IsCurrent(surface) always returns true if surface is
NULL, so we'd never null things (it downgrades to a check for the context being
current).

         !virtual_context->IsCurrent(surface)) {
       if (!real_context_->MakeCurrent(surface)) {
         return false;
@@ -581,7 +581,7 @@ bool VirtualGLApi::MakeCurrent(GLContext* virtual_context, GLSurface* surface) {
   SetGLApi(this);
 
   virtual_context->SetCurrent(surface);
-  if (!surface->OnMakeCurrent(virtual_context)) {
+  if (surface && !surface->OnMakeCurrent(virtual_context)) {
     LOG(ERROR) << "Could not make GLSurface current.";
     return false;
   }