Add mojo::StrongBindingSet and use it in GeolocationServiceContext.

mojo/common/BUILD.gn

 # 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.
 
 import("//testing/test.gni")
 
 group("common") {
   public_deps = [
     ":common_base",
     ":url_type_converters",
   ]
 }
 
 # GYP version: mojo/mojo_base.gyp:mojo_common_lib
 component("common_base") {
   output_name = "mojo_common_lib"
 
   sources = [
     "common_type_converters.cc",
     "common_type_converters.h",
     "data_pipe_drainer.cc",
     "data_pipe_drainer.h",
     "data_pipe_file_utils.cc",
     "data_pipe_utils.cc",
     "data_pipe_utils.h",
+    "strong_binding_set.h",
     "user_agent.cc",
     "user_agent.h",
     "weak_binding_set.h",
     "weak_interface_ptr_set.h",
   ]
 
   defines = [ "MOJO_COMMON_IMPLEMENTATION" ]
 
   public_deps = [
     "//mojo/public/cpp/system",
@@ skipping 41 matching lines @@
 test("mojo_common_unittests") {
   deps = [
     ":common",
     "//base",
     "//base:message_loop_tests",
     "//base/test:test_support",
     "//mojo/environment:chromium",
     "//mojo/message_pump",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/test_support:test_utils",
+    "//mojo/public/interfaces/bindings/tests:test_interfaces",
     "//testing/gtest",
     "//third_party/mojo/src/mojo/edk/test:run_all_unittests",
     "//third_party/mojo/src/mojo/edk/test:test_support",
     "//url",
   ]
 
   sources = [
     # The message_pump tests are so small and some what related to this code
     # that we put them here.
     "../message_pump/handle_watcher_unittest.cc",
     "../message_pump/message_pump_mojo_unittest.cc",
     "common_type_converters_unittest.cc",
+    "strong_binding_set_unittest.cc",
   ]
 }
 
 test("mojo_common_perftests") {
   deps = [
     ":common",
     "//base",
     "//mojo/environment:chromium",
     "//mojo/message_pump",
     "//mojo/public/cpp/test_support:test_utils",
     "//testing/gtest",
     "//third_party/mojo/src/mojo/edk/test:run_all_perftests",
   ]
 
   sources = [
     "../message_pump/handle_watcher_perftest.cc",
   ]
 }