Initial ui/gl updates for Mac Sky shell target

ui/gl/gl_context_mac.mm

Index: ui/gl/gl_context_mac.mm
diff --git a/ui/gl/gl_context_x11.cc b/ui/gl/gl_context_mac.mm
similarity index 50%
copy from ui/gl/gl_context_x11.cc
copy to ui/gl/gl_context_mac.mm
index b17364de1d2e57e4145191be20da3e91e43a858c..389b80dd0a86f28bca0f36e4792a44e3d85d9e03 100644
--- a/ui/gl/gl_context_x11.cc
+++ b/ui/gl/gl_context_mac.mm
@@ -2,21 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "ui/gl/gl_context.h"
-
+#include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/trace_event/trace_event.h"
-#include "ui/gl/gl_bindings.h"
-#include "ui/gl/gl_context_egl.h"
-#include "ui/gl/gl_context_glx.h"
-#include "ui/gl/gl_context_osmesa.h"
+#include "ui/gl/gl_context_cgl.h"
 #include "ui/gl/gl_context_stub.h"
 #include "ui/gl/gl_implementation.h"
-#include "ui/gl/gl_surface_egl.h"
-#include "ui/gl/gl_surface_glx.h"
-#include "ui/gl/gl_surface_osmesa.h"
-#include "ui/gl/gl_surface_stub.h"
+#include "ui/gl/gl_surface.h"
+#include "ui/gl/gl_switches.h"
 
 namespace gfx {
 
@@ -28,22 +22,14 @@ scoped_refptr<GLContext> GLContext::CreateGLContext(
     GpuPreference gpu_preference) {
   TRACE_EVENT0("gpu", "GLContext::CreateGLContext");
   switch (GetGLImplementation()) {
-    case kGLImplementationOSMesaGL: {
-      scoped_refptr<GLContext> context(new GLContextOSMesa(share_group));
-      if (!context->Initialize(compatible_surface, gpu_preference))
-        return NULL;
-
-      return context;
-    }
-    case kGLImplementationDesktopGL: {
-      scoped_refptr<GLContext> context(new GLContextGLX(share_group));
-      if (!context->Initialize(compatible_surface, gpu_preference))
-        return NULL;
-
-      return context;
-    }
-    case kGLImplementationEGLGLES2: {
-      scoped_refptr<GLContext> context(new GLContextEGL(share_group));
+    case kGLImplementationDesktopGL:
+    case kGLImplementationAppleGL: {
+      scoped_refptr<GLContext> context;
+      // Note that with virtualization we might still be able to make current
+      // 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());
+      context = new GLContextCGL(share_group);
       if (!context->Initialize(compatible_surface, gpu_preference))
         return NULL;