[ios] Use chrome_browser_state_forward.h in /ios/chrome/browser/crash_report/breadcrumbs

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=michaeldo@chromium.org

Bug: 1042208
Change-Id: I859020ffb6010934dd360e4364546c06465d3281
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2010783
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Mike Dougherty <michaeldo@chromium.org>
Commit-Queue: Mike Dougherty <michaeldo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733846}

ios/chrome/browser/crash_report/breadcrumbs/breadcrumb_manager_keyed_service_factory.h

@@ -7,13 +7,10 @@
 
 #include "base/no_destructor.h"
 #include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state_forward.h"
 
 class BreadcrumbManagerKeyedService;
 
-namespace ios {
-class ChromeBrowserState;
-}
-
 class BreadcrumbManagerKeyedServiceFactory
     : public BrowserStateKeyedServiceFactory {
  public:

ios/chrome/browser/crash_report/breadcrumbs/breadcrumb_persistent_storage_keyed_service_factory.h

@@ -7,13 +7,10 @@
 
 #include "base/no_destructor.h"
 #include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state_forward.h"
 
 class BreadcrumbPersistentStorageKeyedService;
 
-namespace ios {
-class ChromeBrowserState;
-}
-
 class BreadcrumbPersistentStorageKeyedServiceFactory
     : public BrowserStateKeyedServiceFactory {
  public: