Remove isolated app code from iOS's chrome_browser_state_io_data.

ios/chrome/browser/browser_state/chrome_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_CHROME_BROWSER_BROWSER_STATE_CHROME_BROWSER_STATE_H_
 #define IOS_CHROME_BROWSER_BROWSER_STATE_CHROME_BROWSER_STATE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 108 matching lines @@
   virtual net::SSLConfigService* GetSSLConfigService() = 0;
 
   // Creates the main net::URLRequestContextGetter that will be returned by
   // GetRequestContext(). Should only be called once.
   virtual net::URLRequestContextGetter* CreateRequestContext(
       std::map<std::string,
                linked_ptr<net::URLRequestJobFactory::ProtocolHandler>>*
           protocol_handlers,
       ScopedVector<net::URLRequestInterceptor> request_interceptors) = 0;
 
-  // Creates a isolated net::URLRequestContextGetter. Should only be called once
-  // per partition_path per browser state object.
-  virtual net::URLRequestContextGetter* CreateIsolatedRequestContext(
-      const base::FilePath& partition_path) = 0;
-
   // Returns the current ChromeBrowserState casted as a TestChromeBrowserState
   // or null if it is not a TestChromeBrowserState.
   // TODO(crbug.com/583682): This method should not be used. It is there for
   // supporting a legacy test, and will be removed as soon as the deprecated
   // test is removed.
   virtual TestChromeBrowserState* AsTestChromeBrowserState();
 
   // web::BrowserState
   net::URLRequestContextGetter* GetRequestContext() override;
 
  protected:
   ChromeBrowserState();
 
  private:
   friend class ::TestChromeBrowserState;
   friend class ::TestChromeBrowserStateManager;
 
   scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserState);
 };
 
 }  // namespace ios
 
 #endif  // IOS_CHROME_BROWSER_BROWSER_STATE_CHROME_BROWSER_STATE_H_