compositor_unittests target is unimplmented on Mac

ui/gfx/gl/gl_context_mac.mm

 // Copyright (c) 2011 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 "base/basictypes.h"
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
 #include "base/memory/scoped_generic_obj.h"
 #include "base/memory/scoped_ptr.h"
 #include "third_party/mesa/MesaLib/include/GL/osmesa.h"
 #include "ui/gfx/gl/gl_bindings.h"
 #include "ui/gfx/gl/gl_context_cgl.h"
 #include "ui/gfx/gl/gl_context_osmesa.h"
 #include "ui/gfx/gl/gl_context_stub.h"
 #include "ui/gfx/gl/gl_implementation.h"
-#include "ui/gfx/gl/gl_surface_cgl.h"
-#include "ui/gfx/gl/gl_surface_osmesa.h"
+#include "ui/gfx/gl/gl_surface.h"
+
+#if defined(USE_WEBKIT_COMPOSITOR)
+#include "ui/gfx/gl/gl_context_nsview.h"
+#endif
 
 namespace {
 
 // ScopedGenericObj functor for CGLDestroyRendererInfo().
 class ScopedDestroyRendererInfo {
  public:
   void operator()(CGLRendererInfoObj x) const {
     CGLDestroyRendererInfo(x);
   }
 };
 
 }  // namespace
 
 namespace gfx {
 
 class GLShareGroup;
 
 scoped_refptr<GLContext> GLContext::CreateGLContext(
     GLShareGroup* share_group,
     GLSurface* compatible_surface,
     GpuPreference gpu_preference) {
   switch (GetGLImplementation()) {
     case kGLImplementationDesktopGL: {
-      scoped_refptr<GLContext> context(new GLContextCGL(share_group));
-      if (!context->Initialize(compatible_surface, gpu_preference))
-        return NULL;
+      scoped_refptr<GLContext> context;
+      if (compatible_surface->IsOffscreen()) {
+        context = new GLContextCGL(share_group);
+        if (!context->Initialize(compatible_surface, gpu_preference))
+          return NULL;
+      } else {
+#if defined(USE_WEBKIT_COMPOSITOR)
+        context = new GLContextNSView(share_group);
+        if (!context->Initialize(compatible_surface, gpu_preference))
+          return NULL;
+#endif
+      }
 
       return context;
     }
     case kGLImplementationOSMesaGL: {
       scoped_refptr<GLContext> context(new GLContextOSMesa(share_group));
       if (!context->Initialize(compatible_surface, gpu_preference))
         return NULL;
 
       return context;
     }
@@ skipping 80 matching lines @@
   }
 
   if (found_online && found_offline) {
     supports_dual_gpus = true;
   }
 
   return supports_dual_gpus;
 }
 
 }  // namespace gfx