Plumb audio focus support for spitzer clients.

content/browser/media/android/media_web_contents_observer_android.cc

Index: content/browser/media/android/media_web_contents_observer_android.cc
diff --git a/content/browser/media/android/media_web_contents_observer_android.cc b/content/browser/media/android/media_web_contents_observer_android.cc
index f5f53b36459d8f185b7164d162338c8414864424..5bb943137df8ddca5ed01ecb25c41510b0d9499f 100644
--- a/content/browser/media/android/media_web_contents_observer_android.cc
+++ b/content/browser/media/android/media_web_contents_observer_android.cc
@@ -4,6 +4,7 @@
 
 #include "content/browser/media/android/media_web_contents_observer_android.h"
 
+#include "base/callback.h"
 #include "content/browser/media/android/browser_media_player_manager.h"
 #include "content/browser/media/android/browser_media_session_manager.h"
 #include "content/browser/media/android/media_session.h"
@@ -87,6 +88,14 @@ void MediaWebContentsObserverAndroid::RenderFrameDeleted(
     RenderFrameHost* render_frame_host) {
   MediaWebContentsObserver::RenderFrameDeleted(render_frame_host);
 
+  const int routing_id = render_frame_host->GetRoutingID();
+  for (auto it = focus_waiters_.begin(); it != focus_waiters_.end();) {
+    if (it->first == routing_id)
+      it = focus_waiters_.erase(it);
+    else
+      ++it;
+  }
+
   for (auto it = media_session_map_.begin(); it != media_session_map_.end();) {
     if (it->first.first == render_frame_host)
       it = media_session_map_.erase(it);
@@ -132,6 +141,23 @@ bool MediaWebContentsObserverAndroid::OnMessageReceived(
   return false;
 }
 
+void MediaWebContentsObserverAndroid::WaitForAudioFocusAsyncInternal(
+    int render_frame_id,
+    const base::Closure& focus_cb) {
+  // See if audio focus has already been approved for the given render frame; we
+  // don't care which delegate it corresponds to, just that one has approval and
+  // is actively playing audio.
+  for (const auto& kv : media_session_map_) {
+    if (kv.first.first->GetRoutingID() == render_frame_id &&
+        kv.second->is_playing()) {

[mlamouri (slow - plz ping), 2016/02/03 15:20:51]

Couldn't a controller be playing even though it doesn't have the right kind of
audio focus?

+      focus_cb.Run();
+      return;
+    }
+  }
+
+  focus_waiters_.push_back(FocusWaiter(render_frame_id, focus_cb));
+}
+
 void MediaWebContentsObserverAndroid::OnMediaPlayerDelegateMessageReceived(
     const IPC::Message& msg,
     RenderFrameHost* render_frame_host) {
@@ -297,20 +323,34 @@ void MediaWebContentsObserverAndroid::OnMediaPlaying(
   // In this case, try to reinitialize it with the new settings.  If they are
   // the same, this is a no-op.  If the reinitialize fails, destroy the
   // controller. A later playback attempt will create a new controller.
-  auto it = media_session_map_.find(id);
-  if (it != media_session_map_.end()) {
-    if (!it->second->Initialize(has_audio, is_remote, duration))
-      media_session_map_.erase(it);
-    return;
+  auto session_it = media_session_map_.find(id);
+  if (session_it != media_session_map_.end()) {
+    if (!session_it->second->Initialize(has_audio, is_remote, duration)) {
+      media_session_map_.erase(session_it);
+      return;
+    }
+  } else {
+    scoped_ptr<MediaSessionController> controller(
+        new MediaSessionController(id, this));
+
+    if (!controller->Initialize(has_audio, is_remote, duration))
+      return;
+
+    media_session_map_[id] = std::move(controller);
   }
 
-  scoped_ptr<MediaSessionController> controller(
-      new MediaSessionController(id, this));
-
-  if (!controller->Initialize(has_audio, is_remote, duration))
-    return;
-
-  media_session_map_[id] = std::move(controller);
+  // Notify all focus waiters for the render frame that audio output is allowed,
+  // delegates will still pause audio as necessary in response to focus changes
+  // from the media session.
+  const int routing_id = render_frame_host->GetRoutingID();
+  for (auto it = focus_waiters_.begin(); it != focus_waiters_.end();) {
+    if (it->first == routing_id) {
+      it->second.Run();
+      it = focus_waiters_.erase(it);
+    } else {
+      ++it;
+    }
+  }
 }
 
 }  // namespace content