Refactor GL bindings so there is no global GLApi or DriverGL.

ui/gl/init/gl_initializer_ozone.cc

 // Copyright 2016 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.
 
 #include "ui/gl/init/gl_initializer.h"
 
 #include "base/logging.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_egl_api_implementation.h"
 #include "ui/gl/gl_gl_api_implementation.h"
@@ skipping 29 matching lines @@
   switch (GetGLImplementation()) {
     case kGLImplementationEGLGLES2:
       if (!GLSurfaceEGL::InitializeOneOff(
               GetSurfaceFactoryOzone()->GetNativeDisplay())) {
         LOG(ERROR) << "GLSurfaceEGL::InitializeOneOff failed.";
         return false;
       }
       return true;
     case kGLImplementationOSMesaGL:
     case kGLImplementationMockGL:
+    case kGLImplementationStubGL:
       return true;
     default:
       return false;
   }
 }
 
 bool InitializeStaticGLBindings(GLImplementation implementation) {
   // Prevent reinitialization with a different implementation. Once the gpu
   // unit tests have initialized with kGLImplementationMock, we don't want to
   // later switch to another GL implementation.
   DCHECK_EQ(kGLImplementationNone, GetGLImplementation());
 
   if (HasGLOzone(implementation)) {
     return GetGLOzone(implementation)
         ->InitializeStaticGLBindings(implementation);
   }
 
   switch (implementation) {
     case kGLImplementationOSMesaGL:
       return InitializeStaticGLBindingsOSMesaGL();
     case kGLImplementationEGLGLES2:
       return InitializeStaticEGLInternal();
     case kGLImplementationMockGL:
-      SetGLImplementation(kGLImplementationMockGL);
+    case kGLImplementationStubGL:
+      SetGLImplementation(implementation);
       InitializeStaticGLBindingsGL();
       return true;
     default:
       NOTREACHED();
   }
 
   return false;
 }
 
 void InitializeDebugGLBindings() {
@@ skipping 14 matching lines @@
     return;
   }
 
   ClearBindingsEGL();
   ClearBindingsGL();
   ClearBindingsOSMESA();
 }
 
 }  // namespace init
 }  // namespace gl