Change the way libc++ is linked when use_custom_libcxx=1.

build/common.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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 3766 matching lines @@
               }],
             ],
           }],
           ['use_instrumented_libraries==1', {
             'dependencies': [
               '<(DEPTH)/third_party/instrumented_libraries/instrumented_libraries.gyp:instrumented_libraries',
             ],
           }],
           ['use_custom_libcxx==1', {
             'dependencies': [
-              '<(DEPTH)/third_party/libc++/libc++.gyp:libc++',
-              '<(DEPTH)/third_party/libc++abi/libc++abi.gyp:libc++abi',
+              '<(DEPTH)/third_party/libc++/libc++.gyp:libcxx_proxy',
             ],
           }],
           ['order_profiling!=0 and (chromeos==1 or OS=="linux" or OS=="android")', {
             'target_conditions' : [
               ['_toolset=="target"', {
                 'cflags': [
                   '-finstrument-functions',
                   # Allow mmx intrinsics to inline, so that the
                   #0 compiler can expand the intrinsics.
                   '-finstrument-functions-exclude-file-list=mmintrin.h',
@@ skipping 1435 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }