Avoid calling into the ContentBrowserClient interface from ResourceDispatcherHostImpl to determine …

content/public/browser/resource_dispatcher_host.h

 // Copyright (c) 2012 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_PUBLIC_BROWSER_RESOURCE_DISPATCHER_HOST_H_
 #define CONTENT_PUBLIC_BROWSER_RESOURCE_DISPATCHER_HOST_H_
 
 #include <stdint.h>
 
 #include <memory>
+#include <string>
 
 #include "base/callback_forward.h"
 #include "content/common/content_export.h"
 
 namespace net {
 class URLRequest;
 }
 
 namespace content {
 
 class DownloadItem;
 class ResourceContext;
 class ResourceDispatcherHostDelegate;
 struct DownloadSaveInfo;
 struct Referrer;
 class RenderFrameHost;
 
+// This callback is invoked when the interceptor finishes processing the
+// header.
+typedef base::Callback<void(bool, int)> OnHeaderProcessedCallback;
+
+// This callback is registered by interceptors who are interested in being
+// notified of certain HTTP headers in outgoing requests. For e.g. Origin.

[jam, 2016/08/10 00:19:26]

nit: please document the parameters to this callback. ditto for above

[ananta, 2016/08/10 00:30:02]

Done.

+typedef base::Callback<void(const std::string&, const std::string&, int,
+                            ResourceContext*, OnHeaderProcessedCallback)>
+    InterceptorCallback;
+
 class CONTENT_EXPORT ResourceDispatcherHost {
  public:
   // Returns the singleton instance of the ResourceDispatcherHost.
   static ResourceDispatcherHost* Get();
 
   // Causes all new requests for the root RenderFrameHost and its children to be
   // blocked (not being started) until ResumeBlockedRequestsForFrameFromUI is
   // called.
   static void BlockRequestsForFrameFromUI(RenderFrameHost* root_frame_host);
 
   // Resumes any blocked request for the specified root RenderFrameHost and
   // child frame hosts.
   static void ResumeBlockedRequestsForFrameFromUI(
       RenderFrameHost* root_frame_host);
 
   // This does not take ownership of the delegate. It is expected that the
   // delegate have a longer lifetime than the ResourceDispatcherHost.
   virtual void SetDelegate(ResourceDispatcherHostDelegate* delegate) = 0;
 
   // Controls whether third-party sub-content can pop-up HTTP basic auth
   // dialog boxes.
   virtual void SetAllowCrossOriginAuthPrompt(bool value) = 0;
 
   // Clears the ResourceDispatcherHostLoginDelegate associated with the request.
   virtual void ClearLoginDelegateForRequest(net::URLRequest* request) = 0;
 
+  // Registers the |interceptor| for the |http_header| passed in.
+  // The |starts_with| parameter is used to match the prefix of the
+  // |http_header| in the response and the interceptor will be invoked if there
+  // is a match. If the |starts_with| parameter is empty, the interceptor will
+  // be invoked for every occurrence of the |http_header|.
+  // Currently only HTTP header based interceptors are supported.
+  // In the future to register a generic interceptor, we could pass in empty
+  // strings for the |http_header| and |starts_with| parameters.

[jam, 2016/08/10 00:19:26]

nit: I'd remove these two lines since we don't need to document possible future
APIs. Specifically, I don't think we'd ever want to filter for all requests
since that would go against the goal of not slowing down the general code path

[ananta, 2016/08/10 00:30:02]

Done.

+  // At the moment we only support one interceptor per |http_header|.
+  virtual void RegisterInterceptor(
+      const std::string& http_header,
+      const std::string& starts_with,
+      const InterceptorCallback& interceptor) = 0;
+
  protected:
   virtual ~ResourceDispatcherHost() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_RESOURCE_DISPATCHER_HOST_H_