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

ui/gl/init/gl_factory_mac.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_factory.h"
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/trace_event/trace_event.h"
 #include "ui/gl/gl_bindings.h"
@@ skipping 69 matching lines @@
       // a different onscreen surface with this context later. But we should
       // always be creating the context with an offscreen surface first.
       DCHECK(compatible_surface->IsOffscreen());
       return InitializeGLContext(new GLContextCGL(share_group),
                                  compatible_surface, attribs);
     case kGLImplementationOSMesaGL:
       return InitializeGLContext(new GLContextOSMesa(share_group),
                                  compatible_surface, attribs);
     case kGLImplementationMockGL:
       return new GLContextStub(share_group);
+    case kGLImplementationStubGL: {
+      scoped_refptr<GLContextStub> stub_context =
+          new GLContextStub(share_group);
+      stub_context->SetUseStubApi(true);
+      return stub_context;
+    }
     default:
       NOTREACHED();
       return nullptr;
   }
 }
 
 scoped_refptr<GLSurface> CreateViewGLSurface(gfx::AcceleratedWidget window) {
   TRACE_EVENT0("gpu", "gl::init::CreateViewGLSurface");
   switch (GetGLImplementation()) {
     case kGLImplementationDesktopGL:
     case kGLImplementationDesktopGLCoreProfile:
     case kGLImplementationAppleGL: {
       NOTIMPLEMENTED() << "No onscreen support on Mac.";
       return nullptr;
     }
     case kGLImplementationOSMesaGL: {
       return InitializeGLSurface(new GLSurfaceOSMesaHeadless());
     }
     case kGLImplementationMockGL:
+    case kGLImplementationStubGL:
       return new GLSurfaceStub;
     default:
       NOTREACHED();
       return nullptr;
   }
 }
 
 scoped_refptr<GLSurface> CreateOffscreenGLSurfaceWithFormat(
     const gfx::Size& size, GLSurfaceFormat format) {
   TRACE_EVENT0("gpu", "gl::init::CreateOffscreenGLSurface");
   switch (GetGLImplementation()) {
     case kGLImplementationOSMesaGL:
       format.SetDefaultPixelLayout(GLSurfaceFormat::PIXEL_LAYOUT_RGBA);
       return InitializeGLSurfaceWithFormat(
           new GLSurfaceOSMesa(format, size), format);
     case kGLImplementationDesktopGL:
     case kGLImplementationDesktopGLCoreProfile:
     case kGLImplementationAppleGL:
       return InitializeGLSurfaceWithFormat(
           new NoOpGLSurface(size), format);
     case kGLImplementationMockGL:
+    case kGLImplementationStubGL:
       return new GLSurfaceStub;
     default:
       NOTREACHED();
       return nullptr;
   }
 }
 
 }  // namespace init
 }  // namespace gl