Forward MIME types to BrowserPlugin when a viewer is specified.

content/public/browser/resource_dispatcher_host_delegate.h

Index: content/public/browser/resource_dispatcher_host_delegate.h
diff --git a/content/public/browser/resource_dispatcher_host_delegate.h b/content/public/browser/resource_dispatcher_host_delegate.h
index 598cffbe099eac74157bb64c21ddbd23ff5923c8..c93fec45058374bf298e7dec95e8456d00045ffe 100644
--- a/content/public/browser/resource_dispatcher_host_delegate.h
+++ b/content/public/browser/resource_dispatcher_host_delegate.h
@@ -101,15 +101,23 @@ class CONTENT_EXPORT ResourceDispatcherHostDelegate {
   // If true is returned, a new Stream will be created and OnStreamCreated()
   // will be called with
   // - the |target_id| returned by this function
+  // - If the stream will be rendered in a BrowserPlugin, |view_id| will
+  //   contain a GUID that can be used to uniquely identify it.
   // - a StreamHandle instance for the Stream. The handle contains the URL for
   //   reading the Stream etc.
   // The Stream's origin will be set to |origin|.
+  //
+  // If the stream will be rendered in a BrowserPlugin, |payload| will contain
+  // the data that should be given to the old ResourceHandler to forward to the
+  // renderer process.
   virtual bool ShouldInterceptResourceAsStream(
       content::ResourceContext* resource_context,
       const GURL& url,
       const std::string& mime_type,
       GURL* origin,
-      std::string* target_id);
+      std::string* target_id,
+      std::string* payload,
+      std::string* view_id);

[jam, 2014/05/30 23:04:16]

if my reading is correct, content calls chrome with this method to get a
"view_id", and then it calls it back right after with the view_id that chrome
gave it.

why can't chrome cache this itself in its delegate implementation, based on a
key that is based on the existing parameters?

[Zachary Kuznia, 2014/05/30 23:40:55]

None of the other parameters are guaranteed to be unique.  The target_id could
possibly be used for this purpose, but it will be removed once all the clients
have migrated to the new API.

[jam, 2014/06/02 06:41:53]

I see. Ok, since I'd really like to avoid this extra concept in the public API
as it's chrome-specific, let's make this method and the one below have a first
parameter as the net::URLRequest* to match most of the methods in this
interface. the chrome delegate can then keep its own mapping from
child_id+request_id to target_id+view_id. this method can then drop the
resource_context/url, while the next method can drop all the parameters other
than the StreamHandle since they're accessible from the net::URLRequest

[Zachary Kuznia, 2014/06/05 22:28:22]

Done.

 
   // Informs the delegate that a Stream was created. |target_id| will be filled
   // with the parameter returned by ShouldInterceptResourceAsStream(). The
@@ -120,6 +128,7 @@ class CONTENT_EXPORT ResourceDispatcherHostDelegate {
       int render_process_id,
       int render_view_id,
       const std::string& target_id,
+      const std::string& view_id,
       scoped_ptr<StreamHandle> stream,
       int64 expected_content_size);