getUserMedia: handle the device starting status report.

content/browser/renderer_host/media/video_capture_controller_unittest.cc

Index: content/browser/renderer_host/media/video_capture_controller_unittest.cc
diff --git a/content/browser/renderer_host/media/video_capture_controller_unittest.cc b/content/browser/renderer_host/media/video_capture_controller_unittest.cc
index eacde473aaba2d0af6af532539f5bf958e39d3ad..e3c2305be643dc8be222fc2a41f5478b529565a6 100644
--- a/content/browser/renderer_host/media/video_capture_controller_unittest.cc
+++ b/content/browser/renderer_host/media/video_capture_controller_unittest.cc
@@ -803,4 +803,34 @@ TEST_F(VideoCaptureControllerTest,
   Mock::VerifyAndClearExpectations(client_a_.get());
 }
 
+// Because OnStarted event will be called only once from each device, it's the
+// job of VideoCaptureController to report OnStarted event to all the clients.

[chfremer, 2017/03/02 17:56:10]

I like the test!
For the description comment here I recommend using a sentence that starts with
"Tests that ...". 
The goal of the description comment is to allow the reader quickly understand
what the test does without having to read the actual code.

In this case "Tests that the VideoCaptureController reports OnStarted() to all
clients, even if they connect after VideoCaptureController::OnStarted() has been
invoked."

[braveyao, 2017/03/03 17:53:12]

Done.

+TEST_F(VideoCaptureControllerTest, OnStartedForMultipleClients) {
+  media::VideoCaptureParams session_100;
+  session_100.requested_format = media::VideoCaptureFormat(
+      gfx::Size(320, 240), 30, media::PIXEL_FORMAT_I420);
+  media::VideoCaptureParams session_200 = session_100;
+  media::VideoCaptureParams session_300 = session_100;
+
+  const VideoCaptureControllerID client_a_route_1(1);
+  const VideoCaptureControllerID client_a_route_2(2);
+  const VideoCaptureControllerID client_b_route_1(3);
+
+  controller_->AddClient(client_a_route_1, client_a_.get(), 100, session_100);
+  controller_->AddClient(client_b_route_1, client_b_.get(), 300, session_300);
+  ASSERT_EQ(2, controller_->GetClientCount());
+
+  {
+    InSequence s;
+    // Simulate the OnStarted event from device.
+    EXPECT_CALL(*client_a_, OnStarted(_));
+    EXPECT_CALL(*client_b_, OnStarted(_));
+    device_client_->OnStarted();
+
+    // VideoCaptureController will take care of the OnStarted event for the
+    // clients who join later.
+    EXPECT_CALL(*client_a_, OnStarted(_));
+    controller_->AddClient(client_a_route_2, client_a_.get(), 200, session_200);
+  }
+}
 }  // namespace content