Remove legacy InfoBarViewProtocol.

ios/chrome/browser/infobars/infobar_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_CHROME_BROWSER_INFOBARS_INFOBAR_CONTROLLER_H_
 #define IOS_CHROME_BROWSER_INFOBARS_INFOBAR_CONTROLLER_H_
 
 #import <UIKit/UIKit.h>
 
-@protocol InfoBarViewProtocol;
+@class InfoBarView;
 class InfoBarViewDelegate;
 namespace infobars {
 class InfoBarDelegate;
 }
 
 // InfoBar for iOS acts as a UIViewController for InfoBarView.
 @interface InfoBarController : NSObject
 
 @property(nonatomic, readonly) InfoBarViewDelegate* delegate;
+
 // Designated initializer.
 - (instancetype)initWithDelegate:(InfoBarViewDelegate*)delegate
     NS_DESIGNATED_INITIALIZER;
 
 - (instancetype)init NS_UNAVAILABLE;
 
 // Creates a view and lays out all the infobar elements in it. Will not add
 // it as a subview yet. This method must be overriden in subclasses.
-- (UIView<InfoBarViewProtocol>*)viewForDelegate:
-                                    (infobars::InfoBarDelegate*)delegate
-                                          frame:(CGRect)bounds;
+- (InfoBarView*)viewForDelegate:(infobars::InfoBarDelegate*)delegate
+                          frame:(CGRect)bounds;
 
 // Creates the view.
 - (void)layoutForDelegate:(infobars::InfoBarDelegate*)delegate
                     frame:(CGRect)bounds;
 
 // Detaches view from its delegate.
 // After this function is called, no user interaction can be handled.
 - (void)detachView;
 
 // Returns the actual height in pixels of this infobar instance.
 - (int)barHeight;
 
 // Adjusts visible portion of this infobar.
 - (void)onHeightsRecalculated:(int)newHeight;
 
 // Removes the view.
 - (void)removeView;
 
 // Accesses the view.
-- (UIView<InfoBarViewProtocol>*)view;
+- (InfoBarView*)view;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_INFOBARS_INFOBAR_CONTROLLER_H_