Upstream most of the iOS WebUI support in ios/web/

ios/web/public/browser_state.h

 // 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.
 
 #ifndef IOS_WEB_PUBLIC_BROWSER_STATE_H_
 #define IOS_WEB_PUBLIC_BROWSER_STATE_H_
 
 #include "base/supports_user_data.h"
 
 namespace base {
 class FilePath;
 }
 
 namespace net {
 class URLRequestContextGetter;
 }
 
 namespace web {
 class CertificatePolicyCache;
+class URLDataManagerIOS;
+class URLDataManagerIOSBackend;
+class URLRequestChromeJob;
 
 // This class holds the context needed for a browsing session.
 // It lives on the UI thread. All these methods must only be called on the UI
 // thread.
 class BrowserState : public base::SupportsUserData {
  public:
   ~BrowserState() override;
 
   // static
   static scoped_refptr<CertificatePolicyCache> GetCertificatePolicyCache(
@@ skipping 11 matching lines @@
   // BrowserState.
   virtual net::URLRequestContextGetter* GetRequestContext() = 0;
 
   // Safely cast a base::SupportsUserData to a BrowserState. Returns nullptr
   // if |supports_user_data| is not a BrowserState.
   static BrowserState* FromSupportsUserData(
       base::SupportsUserData* supports_user_data);
 
  protected:
   BrowserState();
+
+ private:
+  friend class URLDataManagerIOS;
+  friend class URLRequestChromeJob;
+
+  // Returns the URLDataManagerIOSBackend instance associated with this
+  // BrowserState, creating it if necessary. Should only be called on the IO
+  // thread.
+  // Not intended for usage outside of //web.
+  URLDataManagerIOSBackend* GetURLDataManagerIOSBackendOnIOThread();
+
+  // The URLDataManagerIOSBackend instance associated with this BrowserState.
+  // Created and destroyed on the IO thread, and should be accessed only from
+  // the IO thread.
+  URLDataManagerIOSBackend* url_data_manager_ios_backend_;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_BROWSER_STATE_H_