[ios] Use chrome_browser_state_forward.h in /ios/chrome/browser/ui/history

Instead of forward declaring ChromeBrowserState in the ios
namespace, use a header. This will allow moving the class
to the global namespace without having to change all the
forward declaration at the same time.

This CL was uploaded by git cl split.

R=sczs@chromium.org

Bug: 1042208
Change-Id: Ia7408640cb544f336e0353da4577c220242f5a91
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2007817
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734028}

ios/chrome/browser/ui/history/history_mediator.h

@@ -7,12 +7,9 @@
 
 #import <Foundation/Foundation.h>
 
+#include "ios/chrome/browser/browser_state/chrome_browser_state_forward.h"
 #import "ios/chrome/browser/ui/table_view/table_view_favicon_data_source.h"
 
-namespace ios {
-class ChromeBrowserState;
-}
-
 @interface HistoryMediator : NSObject<TableViewFaviconDataSource>
 
 // The coordinator's BrowserState.

ios/chrome/browser/ui/history/history_table_view_controller.h

@@ -7,12 +7,9 @@
 
 #import "ios/chrome/browser/ui/table_view/chrome_table_view_controller.h"
 
+#include "ios/chrome/browser/browser_state/chrome_browser_state_forward.h"
 #include "ios/chrome/browser/ui/history/history_consumer.h"
 
-namespace ios {
-class ChromeBrowserState;
-}
-
 enum class UrlLoadStrategy;
 
 @class ContextMenuCoordinator;

ios/chrome/browser/ui/history/ios_browsing_history_driver.h

@@ -11,16 +11,13 @@
 #include "base/memory/weak_ptr.h"
 #include "components/history/core/browser/browsing_history_driver.h"
 #include "components/history/core/browser/browsing_history_service.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state_forward.h"
 #include "url/gurl.h"
 
 namespace history {
 class HistoryService;
 }
 
-namespace ios {
-class ChromeBrowserState;
-}
-
 @protocol HistoryConsumer;
 
 // A simple implementation of BrowsingHistoryServiceHandler that delegates to