Initial version of onbufferedamountlow

BUG=496700

Review URL: https://codereview.chromium.org/1161133005

Cr-Commit-Position: refs/heads/master@{#341327}

4 files changed, 38 insertions, 3 deletions

diff --git a/components/test_runner/mock_webrtc_data_channel_handler.h b/components/test_runner/mock_webrtc_data_channel_handler.h
index 46df5e67..e23a61b 100644
--- a/components/test_runner/mock_webrtc_data_channel_handler.h
+++ b/components/test_runner/mock_webrtc_data_channel_handler.h
@@ -33,9 +33,8 @@ class MockWebRTCDataChannelHandler : public blink::WebRTCDataChannelHandler {
   virtual blink::WebString protocol() const override;
   virtual bool negotiated() const override;
   virtual unsigned short id() const override;
-  // TODO(bemasc): Mark |state()| as |override| once https://codereview.chromium.org/782843003/
-  // lands in Blink and rolls into Chromium.
-  virtual blink::WebRTCDataChannelHandlerClient::ReadyState state() const;
+  virtual blink::WebRTCDataChannelHandlerClient::ReadyState state() const
+      override;
   virtual unsigned long bufferedAmount() override;
   virtual bool sendStringData(const blink::WebString& data) override;
   virtual bool sendRawData(const char* data, size_t size) override;
diff --git a/content/renderer/media/rtc_data_channel_handler.cc b/content/renderer/media/rtc_data_channel_handler.cc
index fe990df..51fe9e6 100644
--- a/content/renderer/media/rtc_data_channel_handler.cc
+++ b/content/renderer/media/rtc_data_channel_handler.cc
@@ -83,6 +83,17 @@ void RtcDataChannelHandler::Observer::OnStateChange() {
       channel_->state()));
 }
 
+void RtcDataChannelHandler::Observer::OnBufferedAmountChange(
+    uint64 previous_amount) {
+  // Optimization: Only post a task if the change is a decrease, because the web
+  // interface does not perform any action when there is an increase.
+  if (previous_amount > channel_->buffered_amount()) {
+    main_thread_->PostTask(FROM_HERE, base::Bind(
+        &RtcDataChannelHandler::Observer::OnBufferedAmountDecreaseImpl, this,
+        previous_amount));
+  }
+}
+
 void RtcDataChannelHandler::Observer::OnMessage(
     const webrtc::DataBuffer& buffer) {
   // TODO(tommi): Figure out a way to transfer ownership of the buffer without
@@ -100,6 +111,13 @@ void RtcDataChannelHandler::Observer::OnStateChangeImpl(
     handler_->OnStateChange(state);
 }
 
+void RtcDataChannelHandler::Observer::OnBufferedAmountDecreaseImpl(
+    unsigned previous_amount) {
+  DCHECK(main_thread_->BelongsToCurrentThread());
+  if (handler_)
+    handler_->OnBufferedAmountDecrease(previous_amount);
+}
+
 void RtcDataChannelHandler::Observer::OnMessageImpl(
     scoped_ptr<webrtc::DataBuffer> buffer) {
   DCHECK(main_thread_->BelongsToCurrentThread());
@@ -283,6 +301,20 @@ void RtcDataChannelHandler::OnStateChange(
   webkit_client_->didChangeReadyState(convertReadyState(state));
 }
 
+void RtcDataChannelHandler::OnBufferedAmountDecrease(
+    unsigned previous_amount) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DVLOG(1) << "OnBufferedAmountDecrease " << previous_amount;
+
+  if (!webkit_client_) {
+    // If this happens, the web application will not get notified of changes.
+    NOTREACHED() << "WebRTCDataChannelHandlerClient not set.";
+    return;
+  }
+
+  webkit_client_->didDecreaseBufferedAmount(previous_amount);
+}
+
 void RtcDataChannelHandler::OnMessage(scoped_ptr<webrtc::DataBuffer> buffer) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (!webkit_client_) {
diff --git a/content/renderer/media/rtc_data_channel_handler.h b/content/renderer/media/rtc_data_channel_handler.h
index c1ae1336..f93eeca5 100644
--- a/content/renderer/media/rtc_data_channel_handler.h
+++ b/content/renderer/media/rtc_data_channel_handler.h
@@ -60,6 +60,7 @@ class CONTENT_EXPORT RtcDataChannelHandler
 
  private:
   void OnStateChange(webrtc::DataChannelInterface::DataState state);
+  void OnBufferedAmountDecrease(unsigned previous_amount);
   void OnMessage(scoped_ptr<webrtc::DataBuffer> buffer);
   void RecordMessageSent(size_t num_bytes);
 
@@ -86,9 +87,11 @@ class CONTENT_EXPORT RtcDataChannelHandler
 
     // webrtc::DataChannelObserver implementation.
     void OnStateChange() override;
+    void OnBufferedAmountChange(uint64 previous_amount) override;
     void OnMessage(const webrtc::DataBuffer& buffer) override;
 
     void OnStateChangeImpl(webrtc::DataChannelInterface::DataState state);
+    void OnBufferedAmountDecreaseImpl(unsigned previous_amount);
     void OnMessageImpl(scoped_ptr<webrtc::DataBuffer> buffer);
 
     RtcDataChannelHandler* handler_;
diff --git a/content/renderer/media/rtc_data_channel_handler_unittest.cc b/content/renderer/media/rtc_data_channel_handler_unittest.cc
index e33dbbe..7087095 100644
--- a/content/renderer/media/rtc_data_channel_handler_unittest.cc
+++ b/content/renderer/media/rtc_data_channel_handler_unittest.cc
@@ -17,6 +17,7 @@ class MockDataChannelHandlerClient :
   MockDataChannelHandlerClient() : state_(ReadyStateConnecting) {}
 
   void didChangeReadyState(ReadyState state) override { state_ = state; }
+  void didDecreaseBufferedAmount(unsigned previous_amount) override {}
   void didReceiveStringData(const blink::WebString& s) override {}
   void didReceiveRawData(const char* data, size_t size) override {}
   void didDetectError() override {}