Avoid calling into the ContentBrowserClient interface from ResourceDispatcherHostImpl to determine …

content/public/browser/resource_dispatcher_host_interceptor.h

+// Copyright 2016 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_INTERCEPTOR_H_
+#define CONTENT_PUBLIC_BROWSER_RESOURCE_DISPATCHER_HOST_INTERCEPTOR_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+class ResourceContext;
+
+// This class defines an interceptor for the ResourceDispatcherHost. Callers
+// can implement this interface and register it with the ResourceDispatcherHost
+// instance, which will then call methods on this class at various stages of a
+// URL request. Currently only HTTP header based interceptors are supported.
+class CONTENT_EXPORT ResourceDispatcherHostInterceptor {
+ public:
+  typedef base::Callback<void(bool, int)> OnHeaderProcessedCallback;
+
+  ResourceDispatcherHostInterceptor();
+
+  // This callback is invoked when a header which the interceptor has registered
+  // for is found. The contract here is that the caller has to wait for the
+  // processing to finish which will be signaled via a call to the |callback|
+  // function.
+  virtual void OnHttpHeaderReceived(const std::string& header,
+                                    const std::string& value,
+                                    int child_process_id,
+                                    content::ResourceContext* resource_context,
+                                    OnHeaderProcessedCallback callback);

[jam, 2016/08/09 01:36:24]

per https://www.chromium.org/developers/content-module/content-api, since this
is a single-method interface, can this just be a callback parameter to
ResourceDispatcherHost?

[ananta, 2016/08/09 05:47:48]

This could be a callback. Just thinking out aloud, if there would be a similar
use case in RDH where we would need other callbacks. Lets talk tomorrow about
this.

+
+ protected:
+  virtual ~ResourceDispatcherHostInterceptor();
+
+  DISALLOW_COPY_AND_ASSIGN(ResourceDispatcherHostInterceptor);
+};
+
+}  // namespace content.
+
+#endif  // CONTENT_PUBLIC_BROWSER_RESOURCE_DISPATCHER_HOST_INTERCEPTOR_H_