gpu: Bind dummy GL API when no context is current

ui/gl/gl_context_wgl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file implements the GLContextWGL and PbufferGLContext classes.
 
 #include "ui/gl/gl_context_wgl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ skipping 56 matching lines @@
     wglDeleteContext(context_);
     context_ = NULL;
   }
 }
 
 bool GLContextWGL::MakeCurrent(GLSurface* surface) {
   DCHECK(context_);
   if (IsCurrent(surface))
     return true;
 
+  ScopedReleaseCurrent release_current;
   TRACE_EVENT0("gpu", "GLContextWGL::MakeCurrent");
 
   if (!wglMakeCurrent(static_cast<HDC>(surface->GetHandle()), context_)) {
     LOG(ERROR) << "Unable to make gl context current.";
     return false;
   }
 
   // Set this as soon as the context is current, since we might call into GL.
   SetRealGLApi();
 
   SetCurrent(surface);
   if (!InitializeDynamicBindings()) {
-    ReleaseCurrent(surface);
     return false;
   }
 
   if (!surface->OnMakeCurrent(this)) {
     LOG(ERROR) << "Could not make current.";
     return false;
   }
 
+  release_current.Cancel();
   return true;
 }
 
 void GLContextWGL::ReleaseCurrent(GLSurface* surface) {
   if (!IsCurrent(surface))
     return;
 
   SetCurrent(NULL);
   wglMakeCurrent(NULL, NULL);
 }
@@ skipping 27 matching lines @@
   if (gfx::g_driver_wgl.ext.b_WGL_EXT_swap_control) {
     wglSwapIntervalEXT(interval);
   } else {
       LOG(WARNING) <<
           "Could not disable vsync: driver does not "
           "support WGL_EXT_swap_control";
   }
 }
 
 }  // namespace gfx