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

ios/web/shell/view_controller.mm

 // 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.
 
 #import "ios/web/shell/view_controller.h"
 
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
 
 #include "base/mac/objc_property_releaser.h"
 #import "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ios/net/cookies/cookie_store_ios.h"
 #import "ios/net/crn_http_protocol_handler.h"
 #import "ios/net/empty_nsurlcache.h"
 #include "ios/web/public/referrer.h"
 #include "ios/web/public/web_state/web_state.h"
+#import "ios/web/public/web_state/web_state_delegate_bridge.h"
 #import "ios/web/public/web_state/web_state_observer_bridge.h"
 #include "ios/web/shell/shell_browser_state.h"
 #include "ios/web/web_state/ui/crw_web_controller.h"
 #include "ios/web/web_state/web_state_impl.h"
 #include "ui/base/page_transition_types.h"
 
 NSString* const kWebShellBackButtonAccessibilityLabel = @"Back";
 NSString* const kWebShellForwardButtonAccessibilityLabel = @"Forward";
 NSString* const kWebShellAddressFieldAccessibilityLabel = @"Address field";
 
 using web::NavigationManager;
 
-@interface ViewController ()<CRWWebStateObserver> {
+@interface ViewController ()<CRWWebStateDelegate, CRWWebStateObserver> {
   web::BrowserState* _browserState;
   std::unique_ptr<web::WebStateImpl> _webState;
   std::unique_ptr<web::WebStateObserverBridge> _webStateObserver;
+  std::unique_ptr<web::WebStateDelegateBridge> _webStateDelegate;
 
   base::mac::ObjCPropertyReleaser _propertyReleaser_ViewController;
 }
 @property(nonatomic, assign, readonly) NavigationManager* navigationManager;
 @property(nonatomic, readwrite, retain) UITextField* field;
 @end
 
 @implementation ViewController
 
 @synthesize field = _field;
@@ skipping 62 matching lines @@
   // Set up the network stack before creating the WebState.
   [self setUpNetworkStack];
 
   _webState.reset(new web::WebStateImpl(_browserState));
   _webState->GetNavigationManagerImpl().InitializeSession(nil, nil, NO, 0);
   [_webState->GetWebController() setDelegate:self];
   [_webState->GetWebController() setWebUsageEnabled:YES];
 
   _webStateObserver.reset(
       new web::WebStateObserverBridge(_webState.get(), self));
+  _webStateDelegate.reset(new web::WebStateDelegateBridge(self));
+  _webState->SetDelegate(_webStateDelegate.get());
 
   UIView* view = _webState->GetView();
   [view setFrame:[_containerView bounds]];
   [_containerView addSubview:view];
 
   NavigationManager::WebLoadParams params(GURL("https://dev.chromium.org/"));
   params.transition_type = ui::PAGE_TRANSITION_TYPED;
   self.navigationManager->LoadURLWithParams(params);
 }
 
@@ skipping 213 matching lines @@
 - (void)webWillFinishHistoryNavigationFromEntry:(CRWSessionEntry*)fromEntry {
 }
 - (int)downloadImageAtUrl:(const GURL&)url
             maxBitmapSize:(uint32_t)maxBitmapSize
                  callback:
                      (const web::WebState::ImageDownloadCallback&)callback {
   return -1;
 }
 
 @end