Reduce and limit video poster memory usage

chrome/browser/media/android/remote/remote_media_player_manager.cc

Index: chrome/browser/media/android/remote/remote_media_player_manager.cc
diff --git a/chrome/browser/media/android/remote/remote_media_player_manager.cc b/chrome/browser/media/android/remote/remote_media_player_manager.cc
index 375e7e07528e490abe8d991ea7559d27a039404b..351376507edb8bd9e17d39b4ca44ad880de547ab 100644
--- a/chrome/browser/media/android/remote/remote_media_player_manager.cc
+++ b/chrome/browser/media/android/remote/remote_media_player_manager.cc
@@ -12,6 +12,8 @@
 
 using media::MediaPlayerAndroid;
 
+static const int MAX_POSTER_BITMAP_SIZE = 1024 * 1024;
+
 namespace remote_media {
 
 RemoteMediaPlayerManager::RemoteMediaPlayerManager(
@@ -50,6 +52,7 @@ void RemoteMediaPlayerManager::OnDestroyPlayer(int player_id) {
   RemoteMediaPlayerBridge* player = GetRemotePlayer(player_id);
   if (player)
     player->OnPlayerDestroyed();
+  poster_urls_.erase(player_id);
   BrowserMediaPlayerManager::OnDestroyPlayer(player_id);
 }
 
@@ -86,27 +89,30 @@ int RemoteMediaPlayerManager::GetTabId() {
   return tab->GetAndroidId();
 }
 
-void RemoteMediaPlayerManager::OnSetPoster(int player_id, const GURL& url) {
+void RemoteMediaPlayerManager::FetchPosterBitmap(int player_id) {
   RemoteMediaPlayerBridge* player = GetRemotePlayer(player_id);
-
-  if (player && url.is_empty()) {
-    player->SetPosterBitmap(std::vector<SkBitmap>());
-  } else {
-    // TODO(aberent) OnSetPoster is called when the attributes of the video
-    // element are parsed, which may be before OnInitialize is called. We are
-    // here relying on the image fetch taking longer than the delay until
-    // OnInitialize is called, and hence the player is created. This is not
-    // guaranteed.
-    content::WebContents::ImageDownloadCallback callback = base::Bind(
-        &RemoteMediaPlayerManager::DidDownloadPoster,
-        weak_ptr_factory_.GetWeakPtr(), player_id);
-    web_contents()->DownloadImage(
-        url,
-        false,  // is_favicon, false so that cookies will be used.
-        0,  // max_bitmap_size, 0 means no limit.
-        false, // normal cache policy.
-        callback);
+  if (poster_urls_.count(player_id) == 0 ||
+      poster_urls_[player_id].is_empty()) {
+    if (player)
+      player->SetPosterBitmap(std::vector<SkBitmap>());
+    return;
   }
+  content::WebContents::ImageDownloadCallback callback =
+      base::Bind(&RemoteMediaPlayerManager::DidDownloadPoster,
+                 weak_ptr_factory_.GetWeakPtr(), player_id);
+  web_contents()->DownloadImage(
+      poster_urls_[player_id],
+      false,  // is_favicon, false so that cookies will be used.
+      MAX_POSTER_BITMAP_SIZE,  // max_bitmap_size, 0 means no limit.
+      false,                   // normal cache policy.
+      callback);
+}
+
+void RemoteMediaPlayerManager::OnSetPoster(int player_id, const GURL& url) {
+  // OnSetPoster is called when the attibutes of the video element are parsed,
+  // which may be before OnInitialize is called, so we can't assume that the
+  // players wil exist.
+  poster_urls_[player_id] = url;
 }
 
 void RemoteMediaPlayerManager::ReleaseResources(int player_id) {
@@ -171,6 +177,9 @@ void RemoteMediaPlayerManager::SwitchToRemotePlayer(
   Send(new MediaPlayerMsg_DidMediaPlayerPlay(RoutingID(), player_id));
   Send(new MediaPlayerMsg_ConnectedToRemoteDevice(RoutingID(), player_id,
                                                   casting_message));
+  // The remote player will want the poster bitmap, however, to avoid wasting
+  // memory we don't fetch it until we are likely to need it.
+  FetchPosterBitmap(player_id);
 }
 
 void RemoteMediaPlayerManager::SwitchToLocalPlayer(int player_id) {