Media Remoting: Draw remoting interstitial on poster image.

media/remoting/remoting_renderer_controller.h

Index: media/remoting/remoting_renderer_controller.h
diff --git a/media/remoting/remoting_renderer_controller.h b/media/remoting/remoting_renderer_controller.h
index 9c98af12b555441c1ade86ff34291b321c7a8076..35ca9e64dcae16f74d4dc22abeb6e238af6fe46b 100644
--- a/media/remoting/remoting_renderer_controller.h
+++ b/media/remoting/remoting_renderer_controller.h
@@ -9,6 +9,7 @@
 #include "base/memory/weak_ptr.h"
 #include "media/base/media_observer.h"
 #include "media/remoting/remoting_source_impl.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 
 namespace media {
 
@@ -37,9 +38,16 @@ class RemotingRendererController final : public RemotingSourceImpl::Client,
   void OnExitedFullscreen() override;
   void OnSetCdm(CdmContext* cdm_context) override;
   void OnMetadataChanged(const PipelineMetadata& metadata) override;
+  void OnSetPoster(const GURL& poster) override;
 
   void SetSwitchRendererCallback(const base::Closure& cb);
 
+  using DownloadPosterCallback =
+      base::Callback<void(const GURL&,
+                          const base::Callback<void(const SkBitmap&)>&)>;
+  // Set the callback to download poster image. Can only be called once.
+  void SetDownloadPosterCallback(const DownloadPosterCallback& cb);
+
   base::WeakPtr<RemotingRendererController> GetWeakPtr() {
     return weak_factory_.GetWeakPtr();
   }
@@ -90,7 +98,29 @@ class RemotingRendererController final : public RemotingSourceImpl::Client,
   // necessary.
   void UpdateAndMaybeSwitch();
 
-  // Indicates whether this media element or its ancestor is in full screen.
+  // Called to download the poster image. Called when:
+  // 1. Poster URL changes.
+  // 2. ShowInterstitialCallback is set.
+  // 3. DownloadPosterCallback is set.
+  void DownloadPosterImage();
+
+  // Called when poster image is downloaded.
+  void OnPosterImageDownloaded(const GURL& download_url, const SkBitmap& image);
+
+  // Update remoting interstitial with |image|. When |image| is empty,
+  // interstitial will be drawn on previously downloaded poster image (in
+  // RemoteRendererImpl) or black background if none was downloaded before.
+  // TODO(xjz): https://codereview.chromium.org/2566223005/
+  // Call this when:
+  // 1. SetShowInterstitialCallback() is called (RemoteRendererImpl is created).
+  // 2. The remoting session is shut down (to update the status message in the
+  //    interstitial).
+  // 3. The size of the canvas is changed (to update the background image and
+  //    the position of the status message).
+  // 4. Poster image is downloaded (to update the background image).
+  void UpdateInterstitial(const SkBitmap& image);
+
+  // Indicates whether this media element is in full screen.
   bool is_fullscreen_ = false;
 
   // Indicates whether remoting is started.
@@ -114,8 +144,17 @@ class RemotingRendererController final : public RemotingSourceImpl::Client,
   // debug builds.
   base::ThreadChecker thread_checker_;
 
+  // Current pipeline metadata.
   PipelineMetadata pipeline_metadata_;
 
+  // Current poster URL, whose image will feed into the local UI.
+  GURL poster_url_;
+
+  // The callback to download the poster image. Called when |poster_url_|
+  // changes during a remoting session or the show interstial callback is set.
+  // OnPosterImageDownloaded() will be called when download completes.
+  DownloadPosterCallback download_poster_cb_;
+
   base::WeakPtrFactory<RemotingRendererController> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RemotingRendererController);