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

ios/web/public/web_state/web_state.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_PUBLIC_WEB_STATE_WEB_STATE_H_
 #define IOS_WEB_PUBLIC_WEB_STATE_WEB_STATE_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 133 matching lines @@
   // Returns true if the current page is a web view with HTML.
   virtual bool ContentIsHTML() const = 0;
 
   // Returns the current navigation title. This could be the title of the page
   // if it is available or the URL.
   virtual const base::string16& GetTitle() const = 0;
 
   // Returns true if the current page is loading.
   virtual bool IsLoading() const = 0;
 
+  // The fraction of the page load that has completed as a number between 0.0
+  // (nothing loaded) and 1.0 (fully loaded).
+  virtual double GetLoadingProgress() const = 0;
+
   // Whether this instance is in the process of being destroyed.
   virtual bool IsBeingDestroyed() const = 0;
 
   // Gets the URL currently being displayed in the URL bar, if there is one.
   // This URL might be a pending navigation that hasn't committed yet, so it is
   // not guaranteed to match the current page in this WebState. A typical
   // example of this is interstitials, which show the URL of the new/loading
   // page (active) but the security context is of the old page (last committed).
   virtual const GURL& GetVisibleURL() const = 0;
 
@@ skipping 87 matching lines @@
 
   // Returns a WeakPtr<WebState> to the current WebState. Must remain private
   // and only call must be in WebStateWeakPtrFactory. Please consult that class
   // for more details. Remove as part of http://crbug.com/556736.
   virtual base::WeakPtr<WebState> AsWeakPtr() = 0;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_WEB_STATE_WEB_STATE_H_