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

ios/web/web_state/ui/crw_web_controller.h

 // Copyright 2012 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_UI_CRW_WEB_CONTROLLER_H_
 #define IOS_WEB_WEB_STATE_UI_CRW_WEB_CONTROLLER_H_
 
 #import <UIKit/UIKit.h>
 
 #import "ios/web/net/crw_request_tracker_delegate.h"
@@ skipping 80 matching lines @@
 // is not supported.
 @property(nonatomic, readonly) UIView* viewForPrinting;
 
 // Content view was reset due to low memory.  Use placeholder overlay view on
 // next creation.
 @property(nonatomic, readwrite, assign) BOOL usePlaceholderOverlay;
 
 // Returns the current page loading phase.
 @property(nonatomic, readonly) web::LoadPhase loadPhase;
 
+// The fraction of the page load that has completed as a number between 0.0
+// (nothing loaded) and 1.0 (fully loaded).
+@property(nonatomic, readonly) double loadingProgress;
+
 // Returns whether the page can navigate backwards or forwards.
 @property(nonatomic, readonly) BOOL canGoBack;
 @property(nonatomic, readonly) BOOL canGoForward;
 
 // Returns the x, y offset the content has been scrolled.
 @property(nonatomic, readonly) CGPoint scrollPosition;
 
 // Returns whether the top of the content is visible.
 @property(nonatomic, readonly) BOOL atTop;
 
@@ skipping 216 matching lines @@
 
 // Acts on a single message from the JS object, parsed from JSON into a
 // DictionaryValue. Returns NO if the format for the message was invalid.
 - (BOOL)respondToMessage:(base::DictionaryValue*)crwMessage
        userIsInteracting:(BOOL)userIsInteracting
                originURL:(const GURL&)originURL;
 
 @end
 
 #endif  // IOS_WEB_WEB_STATE_UI_CRW_WEB_CONTROLLER_H_