[Ozone] Explicitly whilelist valid GL platforms and fail GL initialization otherwise

ui/gl/gl_surface_ozone.cc

 // Copyright 2014 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/gl_surface.h"
 
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/ozone/surface_factory_ozone.h"
@@ skipping 11 matching lines @@
       if (gfx::SurfaceFactoryOzone::GetInstance()->InitializeHardware() !=
           gfx::SurfaceFactoryOzone::INITIALIZED) {
         LOG(ERROR) << "Ozone failed to initialize hardware";
         return false;
       }
 
       if (!GLSurfaceEGL::InitializeOneOff()) {
         LOG(ERROR) << "GLSurfaceEGL::InitializeOneOff failed.";
         return false;
       }
+
+      return true;
+    case kGLImplementationOSMesaGL:
+    case kGLImplementationMockGL:
+      return true;
     default:
-      break;
+      return false;
   }
-  return true;
 }
 
 // static
 scoped_refptr<GLSurface> GLSurface::CreateViewGLSurface(
     gfx::AcceleratedWidget window) {
   if (GetGLImplementation() == kGLImplementationOSMesaGL) {
     scoped_refptr<GLSurface> surface(new GLSurfaceOSMesaHeadless());
     if (!surface->Initialize())
       return NULL;
     return surface;
@@ skipping 45 matching lines @@
       NOTREACHED();
       return NULL;
   }
 }
 
 EGLNativeDisplayType GetPlatformDefaultEGLNativeDisplay() {
   return SurfaceFactoryOzone::GetInstance()->GetNativeDisplay();
 }
 
 }  // namespace gfx