Add mojo::StrongBindingSet and use it in GeolocationServiceContext.

mojo/mojo_base.gyp

 # Copyright 2014 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.
 
 # Essential components (and their tests) that are needed to build
 # Chrome should be here.  Other components that are useful only in
 # Mojo land like mojo_shell should be in mojo.gyp.
 {
   'includes': [
     '../third_party/mojo/mojo_variables.gypi',
@@ skipping 63 matching lines @@
       ],
       'export_dependent_settings': [
         '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
       ],
       'sources': [
         'common/common_type_converters.cc',
         'common/common_type_converters.h',
         'common/data_pipe_file_utils.cc',
         'common/data_pipe_utils.cc',
         'common/data_pipe_utils.h',
+        'common/strong_binding_set.h',
       ],
     },
     {
       # GN version: //mojo/common:url_type_converters
       'target_name': 'mojo_url_type_converters',
       'type': 'static_library',
       'dependencies': [
         '../base/base.gyp:base',
         '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
         '../url/url.gyp:url_lib',
@@ skipping 33 matching lines @@
       'dependencies': [
         '../base/base.gyp:base',
         '../base/base.gyp:test_support_base',
         '../base/base.gyp:base_message_loop_tests',
         '../testing/gtest.gyp:gtest',
         '../url/url.gyp:url_lib',
         '../third_party/mojo/mojo_edk.gyp:mojo_system_impl',
         '../third_party/mojo/mojo_edk.gyp:mojo_common_test_support',
         '../third_party/mojo/mojo_edk.gyp:mojo_run_all_unittests',
         '../third_party/mojo/mojo_public.gyp:mojo_cpp_bindings',
+        '../third_party/mojo/mojo_public.gyp:mojo_public_test_interfaces_mojom',
         '../third_party/mojo/mojo_public.gyp:mojo_public_test_utils',
         'mojo_common_lib',
         'mojo_environment_chromium',
         'mojo_message_pump_lib',
         'mojo_url_type_converters',
       ],
       'sources': [
         'common/common_type_converters_unittest.cc',
+        'common/strong_binding_set_unittest.cc',
         'message_pump/handle_watcher_unittest.cc',
         'message_pump/message_pump_mojo_unittest.cc',
       ],
     },
     {
       # GN version: //mojo/environment:chromium
       'target_name': 'mojo_environment_chromium',
       'type': 'static_library',
       'dependencies': [
         'mojo_environment_chromium_impl',
@@ skipping 210 matching lines @@
             '../build/isolate.gypi',
           ],
           'sources': [
             'mojo_common_unittests.isolate',
           ],
         },
       ],
     }],
   ]
 }