PlzNavigate: Get StreamPrivate API to work.

extensions/browser/guest_view/mime_handler_view/mime_handler_stream_manager.h

 // Copyright 2015 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 EXTENSIONS_BROWSER_GUEST_VIEW_MIME_HANDLER_VIEW_MIME_HANDLER_STREAM_MANAGER_H_
 #define EXTENSIONS_BROWSER_GUEST_VIEW_MIME_HANDLER_VIEW_MIME_HANDLER_STREAM_MANAGER_H_
 
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/scoped_observer.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "extensions/browser/extension_registry_observer.h"
 
 namespace content {
 class BrowserContext;
+class WebContents;
 }
 
 namespace extensions {
 class Extension;
 class StreamContainer;
 
 // A container for streams that have not yet been claimed by a
 // MimeHandlerViewGuest. If the embedding RenderFrameHost is closed or navigates
 // away from the resource being streamed, the stream is aborted. This is
 // BrowserContext-keyed because mime handlers are extensions, which are
 // per-BrowserContext.
 class MimeHandlerStreamManager : public KeyedService,
                                  public ExtensionRegistryObserver {
  public:
   MimeHandlerStreamManager();
   ~MimeHandlerStreamManager() override;
   static MimeHandlerStreamManager* Get(content::BrowserContext* context);
 
   void AddStream(const std::string& view_id,
                  std::unique_ptr<StreamContainer> stream,
+                 content::WebContents* web_contents,

[jam, 2016/09/14 22:49:52]

why are we passing both WC & RF IDs? it seems we should only have one, since
otherwise there could be bugs where they don't match.

[ananta, 2016/09/15 01:49:17]

Done. As per our discussion, I changed the EmbedderObserver  to cleanup the
stream on the top level frame navigation.

                  int render_process_id,
                  int render_frame_id);
 
   std::unique_ptr<StreamContainer> ReleaseStream(const std::string& view_id);
 
   // ExtensionRegistryObserver override.
   void OnExtensionUnloaded(content::BrowserContext* browser_context,
                            const Extension* extension,
                            UnloadedExtensionInfo::Reason reason) override;
 
@@ skipping 12 matching lines @@
   // EmbedderObserver until it is removed.
   std::map<std::string, std::unique_ptr<EmbedderObserver>> embedder_observers_;
 
   ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
       extension_registry_observer_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_GUEST_VIEW_MIME_HANDLER_VIEW_MIME_HANDLER_STREAM_MANAGER_H_