Implement transfer navigation with mojo

content/browser/loader/resource_request_info_impl.h

Index: content/browser/loader/resource_request_info_impl.h
diff --git a/content/browser/loader/resource_request_info_impl.h b/content/browser/loader/resource_request_info_impl.h
index c54cebb0a3ed61d96c65a7522daa62594acc159d..a9f2ec584995c68a8f5972d0d3a5e7fae9a8e121 100644
--- a/content/browser/loader/resource_request_info_impl.h
+++ b/content/browser/loader/resource_request_info_impl.h
@@ -8,6 +8,7 @@
 #include <memory>
 #include <string>
 
+#include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
@@ -15,6 +16,7 @@
 #include "base/supports_user_data.h"
 #include "content/browser/service_worker/service_worker_context_wrapper.h"
 #include "content/common/resource_request_body_impl.h"
+#include "content/common/url_loader.mojom.h"
 #include "content/public/browser/navigation_ui_data.h"
 #include "content/public/browser/resource_request_info.h"
 #include "content/public/common/referrer.h"
@@ -33,6 +35,10 @@ struct GlobalRoutingID;
 class ResourceRequestInfoImpl : public ResourceRequestInfo,
                                 public base::SupportsUserData::Data {
  public:
+  using TransferCallback =
+      base::Callback<void(mojom::URLLoaderAssociatedRequest,
+                          mojom::URLLoaderClientAssociatedPtr)>;
+
   // Returns the ResourceRequestInfoImpl associated with the given URLRequest.
   CONTENT_EXPORT static ResourceRequestInfoImpl* ForRequest(
       net::URLRequest* request);
@@ -123,7 +129,9 @@ class ResourceRequestInfoImpl : public ResourceRequestInfo,
                          int render_frame_id,
                          int origin_pid,
                          int request_id,
-                         base::WeakPtr<ResourceMessageFilter> filter);
+                         base::WeakPtr<ResourceMessageFilter> filter,
+                         mojom::URLLoaderAssociatedRequest url_loader_request,

[clamy, 2016/11/16 16:38:53]

I don't think ResourceRequestInfo is the right place to do the mojo-related
work, as it's meant to store parameters related to the request and not execute a
lot of logic. I would suggest using content::ResourceLoader instead, if it still
exist in the Mojo world. content::ResourceLoader contains several functions
related to transfers, so I would use this instead.

[yhirano, 2016/11/17 15:23:19]

Thanks. How about having a callback in NavigatorResourceThrottle? ResourceLoader
already has a callback and introducing another one looks a bit confusing to me.

[clamy, 2016/11/21 17:55:54]

Ok after seeing the other patchset, I think the version in ResourceRequestInfo
was better. Can you add more comments about what the callback is used for, and a
DCHECK similar to what I mentioned in NavigationResourceThrottle? Thanks! 

[yhirano, 2016/11/22 08:12:55]

Done. Unfortunately, ResourceRequestInfoImpl doesn't know if mojo-loading is
enabled or not. It is controlled by a runtime flag in the renderer.

+                         mojom::URLLoaderClientAssociatedPtr url_loader_client);
 
   // Whether this request is part of a navigation that should replace the
   // current session history entry. This state is shuffled up and down the stack
@@ -208,6 +216,10 @@ class ResourceRequestInfoImpl : public ResourceRequestInfo,
     return service_worker_context_.get();
   }
 
+  void set_on_transfer(const TransferCallback& on_transfer) {
+    on_transfer_ = on_transfer;
+  }
+
  private:
   FRIEND_TEST_ALL_PREFIXES(ResourceDispatcherHostTest,
                            DeletedFilterDetached);
@@ -252,6 +264,7 @@ class ResourceRequestInfoImpl : public ResourceRequestInfo,
   bool initiated_in_secure_context_;
   std::unique_ptr<NavigationUIData> navigation_ui_data_;
   scoped_refptr<ServiceWorkerContextWrapper> service_worker_context_;
+  TransferCallback on_transfer_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceRequestInfoImpl);
 };