Allow MediaSession in iframes to be routed

content/browser/media/session/media_session_service_router.cc

Index: content/browser/media/session/media_session_service_router.cc
diff --git a/content/browser/media/session/media_session_service_router.cc b/content/browser/media/session/media_session_service_router.cc
new file mode 100644
index 0000000000000000000000000000000000000000..898de9151f64f6bbd3314e11f2cfc77826ee4a29
--- /dev/null
+++ b/content/browser/media/session/media_session_service_router.cc
@@ -0,0 +1,96 @@
+// Copyright 2016 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.
+
+#include "content/browser/media/session/media_session_service_router.h"
+
+#include "content/browser/media/session/media_session_controller.h"
+#include "content/browser/media/session/media_session_impl.h"
+#include "content/browser/media/session/media_session_service_impl.h"
+
+namespace content {
+
+MediaSessionServiceRouter::MediaSessionServiceRouter(MediaSessionImpl* session)
+    : routed_service_(nullptr), session_(session) {}
+
+MediaSessionServiceRouter::~MediaSessionServiceRouter() {}
+
+void MediaSessionServiceRouter::OnServiceCreated(
+    MediaSessionServiceImpl* service) {
+  services_[service->GetRenderFrameHost()] = service;
+}
+
+void MediaSessionServiceRouter::OnServiceDestroyed(
+    MediaSessionServiceImpl* service) {
+  services_.erase(service->GetRenderFrameHost());
+}
+
+void MediaSessionServiceRouter::OnMediaSessionMetadataChanged(
+    MediaSessionServiceImpl* service) {
+  if (service != routed_service_)
+    return;
+
+  session_->NotifyMediaSessionMetadataChange(routed_service_->metadata());
+}
+
+void MediaSessionServiceRouter::OnMediaSessionActionsChanged(
+    MediaSessionServiceImpl* service) {
+  if (service != routed_service_)
+    return;
+
+  session_->NotifyMediaSessionActionsChange(routed_service_->actions());
+}
+
+void MediaSessionServiceRouter::DidReceiveAction(
+    blink::mojom::MediaSessionAction action) {
+  if (routed_service_)

[whywhat, 2016/11/22 23:13:16]

nit: s/routed_service_/!routed_service_

[Zhiqiang Zhang (Slow), 2016/11/25 14:50:41]

Done.

+    return;
+
+  routed_service_->GetClient()->DidReceiveAction(action);
+}
+
+void MediaSessionServiceRouter::MostMeaningfulPlayerObserverMayHaveChanged() {
+  RenderFrameHost* rfh = session_->web_contents()->GetMainFrame();
+  // Prefer top-level session.
+  if (IsServiceActiveForRenderFrameHost(rfh)) {
+    UpdateRoutedService(services_[rfh]);
+    return;
+  }
+
+  // If not, select the most meaningful audio-producing frame.
+  MediaSessionController* controller = static_cast<MediaSessionController*>(
+      session_->GetMostMeaningfulPlayerObserver());
+  if (!controller ||
+      !IsServiceActiveForRenderFrameHost(controller->id().first)) {
+    UpdateRoutedService(nullptr);
+    return;
+  }
+  UpdateRoutedService(services_[controller->id().first]);
+}
+
+bool MediaSessionServiceRouter::IsServiceActiveForRenderFrameHost(
+    RenderFrameHost* rfh) {
+  if (!services_.count(rfh))
+    return false;
+
+  return services_[rfh]->metadata().has_value() ||
+         !services_[rfh]->actions().empty();
+}
+
+void MediaSessionServiceRouter::UpdateRoutedService(
+    MediaSessionServiceImpl* service) {
+  if (service == routed_service_)
+    return;
+
+  routed_service_ = service;
+  if (!routed_service_) {

[whywhat, 2016/11/22 23:13:16]

nit: s/!routed_service/routed_service

[Zhiqiang Zhang (Slow), 2016/11/25 14:50:41]

Done.

+    session_->NotifyMediaSessionMetadataChange(routed_service_->metadata());
+    session_->NotifyMediaSessionActionsChange(routed_service_->actions());
+  } else {
+    session_->NotifyMediaSessionMetadataChange(base::nullopt);
+    session_->NotifyMediaSessionActionsChange(
+        std::set<blink::mojom::MediaSessionAction>());
+  }
+}
+
+}  // namespace content