[ios] Added WebState::GetLoadingProgress web// API.

ios/web/web_state/web_state_impl.mm

 // 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.
 
 #include "ios/web/web_state/web_state_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/strings/sys_string_conversions.h"
@@ skipping 182 matching lines @@
     FOR_EACH_OBSERVER(WebStateObserver, observers_, DidStartLoading());
   } else {
     FOR_EACH_OBSERVER(WebStateObserver, observers_, DidStopLoading());
   }
 }
 
 bool WebStateImpl::IsLoading() const {
   return is_loading_;
 }
 
+double WebStateImpl::GetLoadingProgress() const {
+  return [web_controller_ loadingProgress];
+}
+
 bool WebStateImpl::IsBeingDestroyed() const {
   return is_being_destroyed_;
 }
 
 void WebStateImpl::OnPageLoaded(const GURL& url, bool load_success) {
   if (facade_delegate_)
     facade_delegate_->OnPageLoaded();
 
   PageLoadCompletionStatus load_completion_status =
       load_success ? PageLoadCompletionStatus::SUCCESS
@@ skipping 428 matching lines @@
     const LoadCommittedDetails& load_details) {
   FOR_EACH_OBSERVER(WebStateObserver, observers_,
                     NavigationItemCommitted(load_details));
 }
 
 WebState* WebStateImpl::GetWebState() {
   return this;
 }
 
 }  // namespace web