Add a content_shell flag to turn on partial site isolation.

content/shell/browser/shell_content_browser_client.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 CONTENT_SHELL_BROWSER_SHELL_CONTENT_BROWSER_CLIENT_H_
 #define CONTENT_SHELL_BROWSER_SHELL_CONTENT_BROWSER_CLIENT_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 14 matching lines @@
   static ShellContentBrowserClient* Get();
 
   static void SetSwapProcessesForRedirect(bool swap);
 
   ShellContentBrowserClient();
   ~ShellContentBrowserClient() override;
 
   // ContentBrowserClient overrides.
   BrowserMainParts* CreateBrowserMainParts(
       const MainFunctionParams& parameters) override;
+  bool DoesSiteRequireDedicatedProcess(BrowserContext* browser_context,
+                                       const GURL& effective_url) override;
   net::URLRequestContextGetter* CreateRequestContext(
       BrowserContext* browser_context,
       ProtocolHandlerMap* protocol_handlers,
       URLRequestInterceptorScopedVector request_interceptors) override;
   net::URLRequestContextGetter* CreateRequestContextForStoragePartition(
       BrowserContext* browser_context,
       const base::FilePath& partition_path,
       bool in_memory,
       ProtocolHandlerMap* protocol_handlers,
       URLRequestInterceptorScopedVector request_interceptors) override;
@@ skipping 67 matching lines @@
       resource_dispatcher_host_delegate_;
 
   base::Closure select_client_certificate_callback_;
 
   ShellBrowserMainParts* shell_browser_main_parts_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_BROWSER_SHELL_CONTENT_BROWSER_CLIENT_H_