[ios] Added web// public API to let embedder observe loading progress.

ios/web/ios_web.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.
 
 {
   'variables': {
     'chromium_code': 1,
    },
   'targets': [
     {
@@ skipping 167 matching lines @@
         'public/web_state/page_display_state.h',
         'public/web_state/page_display_state.mm',
         'public/web_state/ui/crw_content_view.h',
         'public/web_state/ui/crw_generic_content_view.h',
         'public/web_state/ui/crw_native_content.h',
         'public/web_state/ui/crw_native_content_provider.h',
         'public/web_state/ui/crw_web_delegate.h',
         'public/web_state/ui/crw_web_view_content_view.h',
         'public/web_state/url_verification_constants.h',
         'public/web_state/web_state.h',
+        'public/web_state/web_state_delegate.h',
+        'public/web_state/web_state_delegate_bridge.h',
         'public/web_state/web_state_observer.h',
         'public/web_state/web_state_observer_bridge.h',
         'public/web_state/web_state_policy_decider.h',
         'public/web_state/web_state_user_data.h',
         'public/web_thread.h',
         'public/web_thread_delegate.h',
         'public/web_ui_ios_data_source.h',
         'public/web_view_creation_util.h',
         'string_util.cc',
         'ui_web_view_util.h',
@@ skipping 51 matching lines @@
         'web_state/ui/crw_wk_web_view_web_controller.mm',
         'web_state/ui/web_view_js_utils.h',
         'web_state/ui/web_view_js_utils.mm',
         'web_state/ui/wk_back_forward_list_item_holder.h',
         'web_state/ui/wk_back_forward_list_item_holder.mm',
         'web_state/ui/wk_web_view_configuration_provider.h',
         'web_state/ui/wk_web_view_configuration_provider.mm',
         'web_state/web_controller_observer_bridge.h',
         'web_state/web_controller_observer_bridge.mm',
         'web_state/web_state.mm',
+        'web_state/web_state_delegate.mm',
+        'web_state/web_state_delegate_bridge.mm',
         'web_state/web_state_facade_delegate.h',
         'web_state/web_state_impl.h',
         'web_state/web_state_impl.mm',
         'web_state/web_state_observer.mm',
         'web_state/web_state_observer_bridge.mm',
         'web_state/web_state_policy_decider.mm',
         'web_state/web_state_weak_ptr_factory.h',
         'web_state/web_state_weak_ptr_factory.mm',
         'web_state/web_view_internal_creation_util.h',
         'web_state/web_view_internal_creation_util.mm',
@@ skipping 187 matching lines @@
       'dependencies': [
         '../../base/base.gyp:base'
       ],
       'sources': [
         'public/user_agent.h',
         'public/user_agent.mm',
       ],
     },
   ],
 }