Convert PeerConnectionTrackerHost_AddPeerConnection to mojo

This is a first step to convert the remaining old IPC messages
in content::PeerConnectionTracker to Mojo. At this time, this CL
converts PeerConnectionTrackerHost_AddPeerConnection.

The remaining messages will be converted on follow up steps.

This paves out the way to Onion souping peer_connection_tracker.cc|h.

BUG=787254
R=dcheng@chromium.org, guidou@chromium.org, haraken@chromium.org

Change-Id: I578bcd21ce68253377be853a5b05876bfa04aa13
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1823619Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Cr-Commit-Position: refs/heads/master@{#700177}

content/browser/renderer_host/media/peer_connection_tracker_host.cc

@@ -24,8 +24,6 @@ bool PeerConnectionTrackerHost::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
 
   IPC_BEGIN_MESSAGE_MAP(PeerConnectionTrackerHost, message)
-    IPC_MESSAGE_HANDLER(PeerConnectionTrackerHost_AddPeerConnection,
-                        OnAddPeerConnection)
     IPC_MESSAGE_HANDLER(PeerConnectionTrackerHost_AddStandardStats,
                         OnAddStandardStats)
     IPC_MESSAGE_HANDLER(PeerConnectionTrackerHost_AddLegacyStats,
@@ -61,20 +59,27 @@ void PeerConnectionTrackerHost::OnChannelClosing() {
   base::PowerMonitor::RemoveObserver(this);
 }
 
-void PeerConnectionTrackerHost::OnAddPeerConnection(
-    const PeerConnectionInfo& info) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+void PeerConnectionTrackerHost::AddPeerConnection(
+    mojom::PeerConnectionInfoPtr info) {
+  // TODO(crbug.com/787254): Remove the thread jump on all the methods
+  // here, and make sure the mojo pipe is bound on the proper thread instead.
+  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
+    base::PostTask(FROM_HERE, {BrowserThread::UI},
+                   base::BindOnce(&PeerConnectionTrackerHost::AddPeerConnection,
+                                  this, std::move(info)));
+    return;
+  }
 
   WebRTCInternals* webrtc_internals = WebRTCInternals::GetInstance();
   if (webrtc_internals) {
     webrtc_internals->OnAddPeerConnection(
-        render_process_id_, peer_pid(), info.lid, info.url,
-        info.rtc_configuration, info.constraints);
+        render_process_id_, peer_pid(), info->lid, info->url,
+        info->rtc_configuration, info->constraints);
   }
 
   WebRtcEventLogger* const logger = WebRtcEventLogger::Get();
   if (logger) {
-    logger->PeerConnectionAdded(render_process_id_, info.lid,
+    logger->PeerConnectionAdded(render_process_id_, info->lid,
                                 base::OnceCallback<void(bool)>());
   }
 }

content/browser/renderer_host/media/peer_connection_tracker_host.h

@@ -14,8 +14,6 @@
 #include "content/public/browser/browser_message_filter.h"
 #include "content/public/browser/browser_thread.h"
 
-struct PeerConnectionInfo;
-
 namespace base {
 class ListValue;
 }  // namespace base
@@ -49,12 +47,12 @@ class PeerConnectionTrackerHost
 
  private:
   // Handlers for IPC messages coming from the renderer.
-  void OnAddPeerConnection(const PeerConnectionInfo& info);
   void OnAddStandardStats(int lid, const base::ListValue& value);
   void OnAddLegacyStats(int lid, const base::ListValue& value);
   void SendOnSuspendOnUIThread();
 
   // mojom::PeerConnectionTrackerHost implementation.
+  void AddPeerConnection(mojom::PeerConnectionInfoPtr info) override;
   void RemovePeerConnection(int lid) override;
   void UpdatePeerConnection(int lid,
                             const std::string& type,

content/common/media/peer_connection_tracker.mojom

@@ -4,6 +4,21 @@
 
 module content.mojom;
 
+struct PeerConnectionInfo {
+  // ID of the peer connection. Unique only within the renderer process.
+  int32 lid;
+
+  // Serialized version of RTCConfiguration.
+  string rtc_configuration;
+
+  // Serialized version of blink::WebMediaConstraints.
+  string constraints;
+
+  // The URL of the blink::WebLocalFrame within which this peer connection
+  // lives. Used for debugging purposes (displayed by WebRTC-Internals).
+  string url;
+};
+
 // This interface allows forwarding PeerConnection events to WebRTCInternals in
 // the browser process.
 interface PeerConnectionTrackerHost {
@@ -11,6 +26,10 @@ interface PeerConnectionTrackerHost {
   // TODO(vm.arjun): Migrate rest of the messages,
   // https://bugs.chromium.org/p/chromium/issues/detail?id=792801
 
+  // Notifies WebRTCInternals about the addition of the peer connection
+  // whose data is specified in |info|.
+  AddPeerConnection(PeerConnectionInfo info);
+
   // Notifies WebRTCInternals about the removal of the peer connection
   // identified with local id |lid|.
   RemovePeerConnection(int32 lid);

content/common/media/peer_connection_tracker_messages.h

@@ -14,21 +14,7 @@
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 #define IPC_MESSAGE_START PeerConnectionTrackerMsgStart
 
-IPC_STRUCT_BEGIN(PeerConnectionInfo)
-  // ID of the peer connection. Unique only within the renderer process.
-  IPC_STRUCT_MEMBER(int, lid)
-  // Serialized version of RTCConfiguration.
-  IPC_STRUCT_MEMBER(std::string, rtc_configuration)
-  // Serialized version of blink::WebMediaConstraints.
-  IPC_STRUCT_MEMBER(std::string, constraints)
-  // The URL of the blink::WebLocalFrame within which this peer connection
-  // lives. Used for debugging purposes (displayed by WebRTC-Internals).
-  IPC_STRUCT_MEMBER(std::string, url)
-IPC_STRUCT_END()
-
 // Messages sent from PeerConnectionTracker to PeerConnectionTrackerHost.
-IPC_MESSAGE_CONTROL1(PeerConnectionTrackerHost_AddPeerConnection,
-                     PeerConnectionInfo /* info */)
 IPC_MESSAGE_CONTROL2(PeerConnectionTrackerHost_AddStandardStats,
                      int /* lid */,
                      base::ListValue /* value */)

content/renderer/media/webrtc/peer_connection_tracker.cc

@@ -708,19 +708,21 @@ void PeerConnectionTracker::RegisterPeerConnection(
   DCHECK(pc_handler);
   DCHECK_EQ(GetLocalIDForHandler(pc_handler), -1);
   DVLOG(1) << "PeerConnectionTracker::RegisterPeerConnection()";
-  PeerConnectionInfo info;
+  auto info = mojom::PeerConnectionInfo::New();
 
-  info.lid = GetNextLocalID();
-  info.rtc_configuration = SerializeConfiguration(config);
+  info->lid = GetNextLocalID();
+  info->rtc_configuration = SerializeConfiguration(config);
 
-  info.constraints = SerializeMediaConstraints(constraints);
+  info->constraints = SerializeMediaConstraints(constraints);
   if (frame)
-    info.url = frame->GetDocument().Url().GetString().Utf8();
+    info->url = frame->GetDocument().Url().GetString().Utf8();
   else
-    info.url = "test:testing";
-  SendTarget()->Send(new PeerConnectionTrackerHost_AddPeerConnection(info));
+    info->url = "test:testing";
 
-  peer_connection_local_id_map_.insert(std::make_pair(pc_handler, info.lid));
+  int32_t lid = info->lid;
+  GetPeerConnectionTrackerHost()->AddPeerConnection(std::move(info));
+
+  peer_connection_local_id_map_.insert(std::make_pair(pc_handler, lid));
 }
 
 void PeerConnectionTracker::UnregisterPeerConnection(

content/renderer/media/webrtc/peer_connection_tracker_unittest.cc

@@ -60,6 +60,7 @@ class MockPeerConnectionTrackerHost : public mojom::PeerConnectionTrackerHost {
   MockPeerConnectionTrackerHost() : binding_(this) {}
   MOCK_METHOD3(UpdatePeerConnection,
                void(int, const std::string&, const std::string&));
+  MOCK_METHOD1(AddPeerConnection, void(mojom::PeerConnectionInfoPtr));
   MOCK_METHOD1(RemovePeerConnection, void(int));
   MOCK_METHOD2(OnPeerConnectionSessionIdSet, void(int, const std::string&));
   MOCK_METHOD5(GetUserMedia,
@@ -119,24 +120,6 @@ std::unique_ptr<blink::WebRTCRtpTransceiver> CreateDefaultTransceiver(
 
 namespace {
 
-class MockSendTargetThread : public MockRenderThread {
- public:
-  MOCK_METHOD1(OnAddPeerConnection, void(PeerConnectionInfo));
-
- private:
-  bool OnMessageReceived(const IPC::Message& msg) override;
-};
-
-bool MockSendTargetThread::OnMessageReceived(const IPC::Message& msg) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(MockSendTargetThread, msg)
-    IPC_MESSAGE_HANDLER(PeerConnectionTrackerHost_AddPeerConnection,
-                        OnAddPeerConnection)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
-}
-
 // TODO(https://crbug.com/868868): Move this into a separate file.
 class MockPeerConnectionHandler : public RTCPeerConnectionHandler {
  public:
@@ -159,24 +142,22 @@ class PeerConnectionTrackerTest : public ::testing::Test {
     tracker_.reset(new PeerConnectionTracker(
         mock_host_->CreateInterfacePtrAndBind(),
         blink::scheduler::GetSingleThreadTaskRunnerForTesting()));
-    target_thread_.reset(new MockSendTargetThread());
-    tracker_->OverrideSendTargetForTesting(target_thread_.get());
   }
 
   void CreateAndRegisterPeerConnectionHandler() {
     mock_handler_.reset(new MockPeerConnectionHandler());
-    EXPECT_CALL(*target_thread_, OnAddPeerConnection(_));
+    EXPECT_CALL(*mock_host_, AddPeerConnection(_));
     tracker_->RegisterPeerConnection(
         mock_handler_.get(),
         webrtc::PeerConnectionInterface::RTCConfiguration(),
         blink::WebMediaConstraints(), nullptr);
+    task_environment_.RunUntilIdle();
   }
 
  protected:
   base::test::SingleThreadTaskEnvironment task_environment_;
   std::unique_ptr<MockPeerConnectionTrackerHost> mock_host_;
   std::unique_ptr<PeerConnectionTracker> tracker_;
-  std::unique_ptr<MockSendTargetThread> target_thread_;
   std::unique_ptr<MockPeerConnectionHandler> mock_handler_;
 };