mac: Weakly link against the CoreBluetooth framework. (attempt #2)

device/bluetooth/bluetooth.gyp

 # Copyright 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 134 matching lines @@
                 'setupapi.dll',
               ],
             },
           },
         }],
         ['OS=="mac"', {
           'link_settings': {
             'libraries': [
               '$(SDKROOT)/System/Library/Frameworks/IOBluetooth.framework',
             ],
+            'conditions': [
+              ['mac_sdk == "10.10"', {
+                'xcode_settings': {
+                  # In the OSX 10.10 SDK, CoreBluetooth became a top level
+                  # framework. Previously, it was nested in IOBluetooth. In
+                  # order for Chrome to run on OSes older than OSX 10.10, the
+                  # top level CoreBluetooth framework must be weakly linked.
+                  'OTHER_LDFLAGS': [
+                    '-weak_framework CoreBluetooth',
+                  ],
+                },
+              }],
+            ],
           },
         }],
       ],
     },
     {
       'target_name': 'uribeacon',
       'type': 'static_library',
       'dependencies': [
         '../../base/base.gyp:base',
       ],
@@ skipping 30 matching lines @@
         'test/mock_bluetooth_gatt_notify_session.cc',
         'test/mock_bluetooth_gatt_notify_session.h',
         'test/mock_bluetooth_gatt_service.cc',
         'test/mock_bluetooth_gatt_service.h',
         'test/mock_bluetooth_socket.cc',
         'test/mock_bluetooth_socket.h',
       ],
     },
   ],
 }