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

ios/web/web_state/web_state_impl.h

 // 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.
 
 #ifndef IOS_WEB_WEB_STATE_WEB_STATE_IMPL_H_
 #define IOS_WEB_WEB_STATE_WEB_STATE_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 215 matching lines @@
   NavigationManager* GetNavigationManager() override;
   CRWJSInjectionReceiver* GetJSInjectionReceiver() const override;
   void ExecuteJavaScript(const base::string16& javascript) override;
   void ExecuteJavaScript(const base::string16& javascript,
                          const JavaScriptResultCallback& callback) override;
   const std::string& GetContentLanguageHeader() const override;
   const std::string& GetContentsMimeType() const override;
   bool ContentIsHTML() const override;
   const base::string16& GetTitle() const override;
   bool IsLoading() const override;
+  double GetLoadingProgress() const override;
   bool IsBeingDestroyed() const override;
   const GURL& GetVisibleURL() const override;
   const GURL& GetLastCommittedURL() const override;
   GURL GetCurrentURL(URLVerificationTrustLevel* trust_level) const override;
   void ShowTransientContentView(CRWContentView* content_view) override;
   bool IsShowingWebInterstitial() const override;
   WebInterstitial* GetWebInterstitial() const override;
   int GetCertGroupId() const override;
   void AddScriptCommandCallback(const ScriptCommandCallback& callback,
                                 const std::string& command_prefix) override;
@@ skipping 104 matching lines @@
   // any WeakPtrs to WebStateImpl are invalidated before its member variable's
   // destructors are executed, rendering them invalid.
   base::WeakPtrFactory<WebState> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebStateImpl);
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_WEB_STATE_WEB_STATE_IMPL_H_