Fix errors found in Mac gn component builds

gpu/command_buffer_service.gypi

 # Copyright (c) 2012 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_dirs': [
     '..',
   ],
   'all_dependent_settings': {
     'include_dirs': [
@@ skipping 124 matching lines @@
     'command_buffer/service/vertex_array_manager.h',
     'command_buffer/service/vertex_attrib_manager.cc',
     'command_buffer/service/vertex_attrib_manager.h',
   ],
   'conditions': [
     ['ui_compositor_image_transport==1', {
       'include_dirs': [
         '../third_party/khronos',
       ],
     }],
+    ['OS=="mac"', {
+      # Required by gles2_cmd_decoder.cc on Mac.
+      'link_settings': {
+        'libraries': [
+          '$(SDKROOT)/System/Library/Frameworks/IOSurface.framework',
+          '$(SDKROOT)/System/Library/Frameworks/OpenGL.framework',

[Dirk Pranke, 2015/04/15 15:48:01]

why is the full path needed here if it's not needed in
gpu/command_buffer/service ?

[Jiang Jiang, 2015/04/15 16:17:20]

I'm not sure what you are referring to, from what I can tell it seems that in
gyp we always use the full path with $(SDKROOT) while in gn we always use the
framework name only, would be tricky to see how we link to
$(SDKROOT)/System/Library/PrivateFrameworks/ in gn though.

[Dirk Pranke, 2015/04/15 16:21:07]

I'm talking about gpu/command_buffer/service/BUILD.gn, where you added the same
two frameworks but only listed the framework names and not the full paths.

[Jiang Jiang, 2015/04/15 16:29:26]

See https://codereview.chromium.org/88813005, so basically what we do in gn by
saying libs = [ "Foo.framework" ] will result a "-framework Foo" being added to
the final linking command.

As for gyp I don't know, blame history refers to commits such as
https://codereview.chromium.org/118473009/. Nico should know better why SDKROOT
was there.

[Dirk Pranke, 2015/04/15 16:34:09]

Oh! I see, I was totally confused and didn't realize this was a GYP file :(.

Never mind ...

+        ],
+      },
+    }],
     ['OS in ("win", "android") or (OS == "linux" and use_x11 == 1)', {
       'sources': [
         'command_buffer/service/async_pixel_transfer_manager_egl.cc',
         'command_buffer/service/async_pixel_transfer_manager_egl.h',
       ],
     }],
   ],
 }