[ios] Fix uses of ios::ChromeBrowserState in /ios/chrome/browser/dom_distiller

The ChromeBrowserState has been moved from the "ios" namespace
to the global namespace by http://crrev.com/c/2014913. Fix the
uses from ios::ChromeBrowserState to ChromeBrowserState.

Also remove includes of chrome_browser_state_forward.h and use
a simple forward declaration instead (since the old name is no
longer necessary).

This CL was uploaded by git cl split.

R=olivierrobin@chromium.org

Bug: 1042208
Change-Id: I1e39b9c33f4b1a99c713f560e10c5d759dd25b5f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2017329Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735364}

ios/chrome/browser/dom_distiller/dom_distiller_service_factory.cc

@@ -57,7 +57,7 @@ DomDistillerServiceFactory* DomDistillerServiceFactory::GetInstance() {
 
 // static
 DomDistillerService* DomDistillerServiceFactory::GetForBrowserState(
-    ios::ChromeBrowserState* browser_state) {
+    ChromeBrowserState* browser_state) {
   return static_cast<DomDistillerKeyedService*>(
       GetInstance()->GetServiceForBrowserState(browser_state, true));
 }
@@ -86,7 +86,7 @@ DomDistillerServiceFactory::BuildServiceInstanceFor(
           std::move(distiller_url_fetcher_factory), options);
   std::unique_ptr<DistilledPagePrefs> distilled_page_prefs =
       std::make_unique<DistilledPagePrefs>(
-          ios::ChromeBrowserState::FromBrowserState(context)->GetPrefs());
+          ChromeBrowserState::FromBrowserState(context)->GetPrefs());
 
   return std::make_unique<DomDistillerKeyedService>(
       std::move(distiller_factory), std::move(distiller_page_factory),

ios/chrome/browser/dom_distiller/dom_distiller_service_factory.h

@@ -10,7 +10,8 @@
 #include "base/macros.h"
 #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 ChromeBrowserState;
 
 namespace dom_distiller {
 class DomDistillerService;
@@ -22,7 +23,7 @@ class DomDistillerServiceFactory : public BrowserStateKeyedServiceFactory {
  public:
   static DomDistillerServiceFactory* GetInstance();
   static DomDistillerService* GetForBrowserState(
-      ios::ChromeBrowserState* browser_state);
+      ChromeBrowserState* browser_state);
 
  private:
   friend class base::NoDestructor<DomDistillerServiceFactory>;