[Presentation API] (MR side) 1-UA: notify receiver page when receiver connection becomes available

chrome/browser/media/router/offscreen_presentation_manager.cc

+// 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.
+
+#include "chrome/browser/media/router/offscreen_presentation_manager.h"
+
+#include <utility>
+
+#include "base/memory/ptr_util.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/web_contents.h"
+
+namespace media_router {
+
+// OffscreenPresentationManager implementation. ////////////////////////////////
+OffscreenPresentationManager::OffscreenPresentationManager() {}
+
+OffscreenPresentationManager::~OffscreenPresentationManager() {}
+
+void OffscreenPresentationManager::RegisterOffscreenPresentationController(
+    const std::string& presentation_id,
+    int render_frame_id,
+    content::OffscreenPresentationClient* controller) {
+  DVLOG(2) << __FUNCTION__ << " [presentation_id]: " << presentation_id
+           << ", [render_frame_id]: " << render_frame_id;
+
+  auto it = offscreen_presentations_.find(presentation_id);
+  // Create a new presentation.
+  if (it == offscreen_presentations_.end()) {
+    it = offscreen_presentations_
+             .insert(std::make_pair(
+                 presentation_id,
+                 base::MakeUnique<OffscreenPresentation>(presentation_id)))
+             .first;
+  }
+  it->second->RegisterController(render_frame_id, controller);
+}
+
+void OffscreenPresentationManager::UnregisterOffscreenPresentationController(
+    const std::string& presentation_id,
+    int render_frame_id) {
+  DVLOG(2) << __FUNCTION__ << " [presentation_id]: " << presentation_id
+           << ", [render_frame_id]: " << render_frame_id;
+
+  auto it = offscreen_presentations_.find(presentation_id);
+  if (it == offscreen_presentations_.end())
+    return;
+
+  // Remove presentation if no controller and receiver.
+  it->second->UnregisterController(render_frame_id);
+  if (it->second->controllers_.size() == 0 &&
+      it->second->receiver_callback_.is_null())
+    offscreen_presentations_.erase(presentation_id);
+}
+
+void OffscreenPresentationManager::RegisterOffscreenPresentationReceiver(
+    const std::string& presentation_id,
+    const content::ReceiverConnectionAvailableCallback& receiver_callback) {
+  DVLOG(2) << __FUNCTION__ << " [presentation_id]: " << presentation_id;
+
+  auto it = offscreen_presentations_.find(presentation_id);
+  if (it != offscreen_presentations_.end())

[imcheng, 2016/09/28 07:28:35]

Does the first RegisterOffscreenPresentationController for an offscreen
presentation always occur before RegisterOffscreenPresentationReceiver? Or would
it be ok to assume that the they can occur in any order?

[zhaobin, 2016/09/29 17:20:43]

They are async so they can occur in any order. Generally
RegisterOffscreenPresentationReceiver occurs later because starting a new render
process takes some time.

+    it->second->RegisterReceiver(receiver_callback);
+}
+
+void OffscreenPresentationManager::UnregisterOffscreenPresentationReceiver(
+    const std::string& presentation_id) {
+  DVLOG(2) << __FUNCTION__ << " [presentation_id]: " << presentation_id;
+  offscreen_presentations_.erase(presentation_id);

[imcheng, 2016/09/28 07:28:35]

question: how do we inform controllers that the receiver has left?

[zhaobin, 2016/09/29 17:20:42]

Receiver PSImpl should have controller's PSImpl (offscreenPresentationClient
API) when unregisterReceiver() is called. Plan to notify controller in
receiver's PSImpl (reset() maybe).

+}
+
+// OffscreenPresentation implementation. ///////////////////////////////////////
+OffscreenPresentation::OffscreenPresentation(const std::string& presentation_id)
+    : presentation_id_(presentation_id), receiver_callback_(nullptr) {}
+
+OffscreenPresentation::~OffscreenPresentation() {}
+
+void OffscreenPresentation::RegisterController(
+    int render_frame_id,
+    content::OffscreenPresentationClient* controller) {
+  // Connect controller PSImpl and receiver PSImpl.
+  if (receiver_callback_) {
+    receiver_callback_.Run(
+        content::PresentationSessionInfo(presentation_url_, presentation_id_),

[imcheng, 2016/09/28 07:28:35]

Looks like we also need to pass in presentation_url to this class?

[zhaobin, 2016/09/29 17:20:43]

Done.

+        controller);
+  } else {
+    controllers_.insert(std::make_pair(render_frame_id, controller));
+  }
+}
+
+void OffscreenPresentation::UnregisterController(int render_frame_id) {
+  controllers_.erase(render_frame_id);
+}
+
+void OffscreenPresentation::RegisterReceiver(
+    const content::ReceiverConnectionAvailableCallback& receiver_callback) {
+  for (const auto& controller : controllers_) {
+    receiver_callback.Run(
+        content::PresentationSessionInfo(presentation_url_, presentation_id_),
+        controller.second);
+  }
+  receiver_callback_ = receiver_callback;
+  controllers_.clear();
+}
+
+}  // namespace media_router