patch from chinmaygarde@ to make progress on mac, ios.

build/config/BUILD.gn

 # Copyright (c) 2013 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.
 
 import("//build/config/allocator.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/module_args/v8.gni")
@@ skipping 368 matching lines @@
     ]
   } else if (is_mac) {
     libs = [
       "AppKit.framework",
       "ApplicationServices.framework",
       "Carbon.framework",
       "CoreFoundation.framework",
       "Foundation.framework",
       "IOKit.framework",
       "Security.framework",
+      "OpenGL.framework",
     ]
   } else if (is_ios) {
+    # The libraries listed here will be specified for both the target and the
+    # host. Only the common ones should be listed here.
     libs = [
       "CoreFoundation.framework",
       "CoreGraphics.framework",
       "CoreText.framework",
       "Foundation.framework",
-      "UIKit.framework",
     ]
   } else if (is_linux) {
     libs = [ "dl" ]
   }
 }
 
 # Add this config to your target to enable precompiled headers.
 #
 # On Windows, precompiled headers are done on a per-target basis. If you have
 # just a couple of files, the time it takes to precompile (~2 seconds) can
@@ skipping 13 matching lines @@
 
     # This is a file that GN will compile with the above header. It will be
     # implicitly added to the sources (potentially multiple times, with one
     # variant for each language used in the target).
     precompiled_source = "//build/precompile.cc"
 
     # Force include the header.
     cflags = [ "/FI$precompiled_header" ]
   }
 }