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

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=gambard@chromium.org

Bug: 1042208
Change-Id: I1b8e0708a07ca1947843688c953e802ff9c663d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2010823
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733339}

ios/chrome/browser/ui/commands/BUILD.gn

@@ -43,6 +43,7 @@ source_set("commands") {
     "//components/browsing_data/core",
     "//components/password_manager/core/browser",
     "//components/signin/public/base",
+    "//ios/chrome/browser/browser_state:forward",
     "//ios/chrome/browser/browsing_data:browsing_data_remove_mask",
   ]
 }

ios/chrome/browser/ui/commands/browsing_data_commands.h

@@ -9,12 +9,9 @@
 
 #import "base/ios/block_types.h"
 #import "components/browsing_data/core/browsing_data_utils.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state_forward.h"
 #include "ios/chrome/browser/browsing_data/browsing_data_remove_mask.h"
 
-namespace ios {
-class ChromeBrowserState;
-}
-
 // Protocol for commands that relate to browsing data.
 @protocol BrowsingDataCommands<NSObject>