Create headerHeightForTab in TabHeadersDelegate.

ios/chrome/browser/ui/fullscreen_controller_unittest.mm

 // 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.
 
 #include "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/ui/fullscreen_controller.h"
 #import "ios/web/public/test/fakes/test_web_view_content_view.h"
 #import "ios/web/public/web_state/crw_web_view_scroll_view_proxy.h"
 #import "ios/web/public/web_state/ui/crw_web_view_content_view.h"
 #import "ios/web/web_state/crw_web_view_proxy_impl.h"
@@ skipping 42 matching lines @@
 }
 
 - (BOOL)isTabWithIDCurrent:(NSString*)sessionID {
   return [self fakeIsTabWithIDCurrentFlag];
 }
 
 - (CGFloat)currentHeaderOffset {
   return currentPosition_;
 }
 
-- (CGFloat)headerHeight {
+- (CGFloat)headerHeightForCurrentTab {
   return kHeaderHeight;
 }
 
+- (CGFloat)headerHeightForTab:(Tab*)tab {
+  return kHeaderHeight;
+}
+
 @end
 
 namespace {
 
 NSString* const kFakeSessionId = @"fake-session-id";
 
 class FullscreenControllerTest : public PlatformTest {
  protected:
   void SetUp() override {
     CGRect frame = CGRectMake(0.0, 0.0, 300.0, 900.0);
@@ skipping 292 matching lines @@
   [controller_ webViewScrollViewDidEndDragging:webViewScrollViewProxy_
                                 willDecelerate:NO];
   EXPECT_TRUE(IsHeaderVisible());
 
   // Hide the keyboard.
   [textField resignFirstResponder];
   EXPECT_TRUE(IsHeaderVisible());
 }
 
 }  // namespace