VideoCaptureDeviceTest: improve error logging

media/capture/video/video_capture_device_unittest.cc

Index: media/capture/video/video_capture_device_unittest.cc
diff --git a/media/capture/video/video_capture_device_unittest.cc b/media/capture/video/video_capture_device_unittest.cc
index 11031fec944b74abf4c0bca026dcd47d6706e7fe..4d97f924dafbd09d6ed23d8f0a1f3b573d1f2ce2 100644
--- a/media/capture/video/video_capture_device_unittest.cc
+++ b/media/capture/video/video_capture_device_unittest.cc
@@ -72,11 +72,17 @@
 #endif
 
 using ::testing::_;
+using ::testing::Invoke;
 using ::testing::SaveArg;
 
 namespace media {
 namespace {
 
+void DumpError(const tracked_objects::Location& location,
+               const std::string& message) {
+  DPLOG(ERROR) << location.ToString() << " " << message;
+}
+
 class MockVideoCaptureClient : public VideoCaptureDevice::Client {
  public:
   MOCK_METHOD0(DoReserveOutputBuffer, void(void));
@@ -90,8 +96,9 @@ class MockVideoCaptureClient : public VideoCaptureDevice::Client {
 
   explicit MockVideoCaptureClient(
       base::Callback<void(const VideoCaptureFormat&)> frame_cb)
-      : main_thread_(base::ThreadTaskRunnerHandle::Get()),
-        frame_cb_(frame_cb) {}
+      : main_thread_(base::ThreadTaskRunnerHandle::Get()), frame_cb_(frame_cb) {
+    ON_CALL(*this, OnError(_, _)).WillByDefault(Invoke(DumpError));

[chfremer, 2016/09/22 18:05:33]

Sgtm. Alternatively, we could use a Lambda expression here, but other than
saving the identifier "DumpError" it does not make a difference, and I think the
way it is now may be easier to read.

+  }
 
   void OnIncomingCapturedData(const uint8_t* data,
                               int length,