Adds UMA histograms for desktop tab and audio capture through

content/browser/media/capture/web_contents_video_capture_device.cc

Index: content/browser/media/capture/web_contents_video_capture_device.cc
diff --git a/content/browser/media/capture/web_contents_video_capture_device.cc b/content/browser/media/capture/web_contents_video_capture_device.cc
index bdadcd2783835a0f5b5be9609d2cd897a218610c..a5d07531988f27c0c759960018034b355c15de12 100644
--- a/content/browser/media/capture/web_contents_video_capture_device.cc
+++ b/content/browser/media/capture/web_contents_video_capture_device.cc
@@ -69,6 +69,7 @@
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "content/browser/media/capture/cursor_renderer.h"
+#include "content/browser/media/capture/desktop_capture_device_uma_types.h"
 #include "content/browser/media/capture/web_contents_tracker.h"
 #include "content/browser/media/capture/window_activity_tracker.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
@@ -260,7 +261,8 @@ class WebContentsCaptureMachine : public media::VideoCaptureMachine {
  public:
   WebContentsCaptureMachine(int render_process_id,
                             int main_render_frame_id,
-                            bool enable_auto_throttling);
+                            bool enable_auto_throttling,
+                            WebContentsVideoCaptureDevice::JavaScriptType type);
   ~WebContentsCaptureMachine() override;
 
   // VideoCaptureMachine overrides.
@@ -329,6 +331,9 @@ class WebContentsCaptureMachine : public media::VideoCaptureMachine {
   // option in the WebContentsVideoCaptureDevice device ID.
   const bool auto_throttling_enabled_;
 
+  bool is_first_capture_;
+  const WebContentsVideoCaptureDevice::JavaScriptType js_type_;
+
   // A dedicated worker thread on which SkBitmap->VideoFrame conversion will
   // occur. Only used when this activity cannot be done on the GPU.
   scoped_ptr<base::Thread> render_thread_;
@@ -629,11 +634,13 @@ void VideoFrameDeliveryLog::ChronicleFrameDelivery(base::TimeTicks frame_time) {
 WebContentsCaptureMachine::WebContentsCaptureMachine(
     int render_process_id,
     int main_render_frame_id,
-    bool enable_auto_throttling)
+    bool enable_auto_throttling,
+    WebContentsVideoCaptureDevice::JavaScriptType type)
     : initial_render_process_id_(render_process_id),
       initial_main_render_frame_id_(main_render_frame_id),
       tracker_(new WebContentsTracker(true)),
       auto_throttling_enabled_(enable_auto_throttling),
+      js_type_(type),
       weak_ptr_factory_(this) {
   DVLOG(1) << "Created WebContentsCaptureMachine for "
            << render_process_id << ':' << main_render_frame_id
@@ -651,6 +658,8 @@ void WebContentsCaptureMachine::Start(
     const scoped_refptr<media::ThreadSafeCaptureOracle>& oracle_proxy,
     const media::VideoCaptureParams& params,
     const base::Callback<void(bool)> callback) {
+  is_first_capture_ = true;
+
   // Starts the capture machine asynchronously.
   BrowserThread::PostTaskAndReplyWithResult(
       BrowserThread::UI,
@@ -866,6 +875,17 @@ void WebContentsCaptureMachine::DidCopyFromBackingStore(
     DVLOG(1) << "CopyFromBackingStore failed; skipping frame.";
     deliver_frame_cb.Run(start_time, gfx::Rect(), false);
   }
+
+  if (is_first_capture_) {
+    is_first_capture_ = false;
+    if (js_type_ ==
+        WebContentsVideoCaptureDevice::CHROME_CHOOSE_DESKTOP_MEDIA) {
+      if (response == READBACK_SUCCESS)

[miu, 2016/03/24 20:51:02]

It's very possible for the first few frames to fail, and this would be normal
behavior.  This is one reason why it doesn't seem useful to UMA-count the first
frame capture (see comment below).

[GeorgeZ, 2016/03/25 16:35:04]

Very valuable comments. I guess this is why a owner's review is necessary.

I will revert all the changes in web_contents_video_capture_device*.*

+        IncrementDesktopCaptureCounter(FIRST_TAB_CAPTURE_SUCCEEDED);
+      else
+        IncrementDesktopCaptureCounter(FIRST_TAB_CAPTURE_FAILED);
+    }
+  }
 }
 
 void WebContentsCaptureMachine::DidCopyFromCompositingSurfaceToVideoFrame(
@@ -883,6 +903,18 @@ void WebContentsCaptureMachine::DidCopyFromCompositingSurfaceToVideoFrame(
     // Capture can fail due to transient issues, so just skip this frame.
     DVLOG(1) << "CopyFromCompositingSurface failed; skipping frame.";
   }
+
+  if (is_first_capture_) {
+    is_first_capture_ = false;
+    if (js_type_ ==
+        WebContentsVideoCaptureDevice::CHROME_CHOOSE_DESKTOP_MEDIA) {
+      if (success)
+        IncrementDesktopCaptureCounter(FIRST_TAB_CAPTURE_SUCCEEDED);
+      else
+        IncrementDesktopCaptureCounter(FIRST_TAB_CAPTURE_FAILED);
+    }
+  }
+
   deliver_frame_cb.Run(start_time, region_in_frame, success);
 }
 
@@ -947,12 +979,14 @@ void WebContentsCaptureMachine::UpdateCaptureSize() {
 WebContentsVideoCaptureDevice::WebContentsVideoCaptureDevice(
     int render_process_id,
     int main_render_frame_id,
-    bool enable_auto_throttling)
+    bool enable_auto_throttling,
+    JavaScriptType type)
     : core_(new media::ScreenCaptureDeviceCore(
-          scoped_ptr<media::VideoCaptureMachine>(new WebContentsCaptureMachine(
-              render_process_id,
-              main_render_frame_id,
-              enable_auto_throttling)))) {}
+          scoped_ptr<media::VideoCaptureMachine>(
+              new WebContentsCaptureMachine(render_process_id,
+                                            main_render_frame_id,
+                                            enable_auto_throttling,
+                                            type)))) {}
 
 WebContentsVideoCaptureDevice::~WebContentsVideoCaptureDevice() {
   DVLOG(2) << "WebContentsVideoCaptureDevice@" << this << " destroying.";
@@ -960,7 +994,8 @@ WebContentsVideoCaptureDevice::~WebContentsVideoCaptureDevice() {
 
 // static
 media::VideoCaptureDevice* WebContentsVideoCaptureDevice::Create(
-    const std::string& device_id) {
+    const std::string& device_id,
+    JavaScriptType type) {
   // Parse device_id into render_process_id and main_render_frame_id.
   int render_process_id = -1;
   int main_render_frame_id = -1;
@@ -969,9 +1004,12 @@ media::VideoCaptureDevice* WebContentsVideoCaptureDevice::Create(
     return NULL;
   }
 
+  if (type == CHROME_CHOOSE_DESKTOP_MEDIA)
+    IncrementDesktopCaptureCounter(TAB_VIDEO_CAPTURER_CREATED);
+
   return new WebContentsVideoCaptureDevice(
       render_process_id, main_render_frame_id,
-      WebContentsMediaCaptureId::IsAutoThrottlingOptionSet(device_id));
+      WebContentsMediaCaptureId::IsAutoThrottlingOptionSet(device_id), type);
 }
 
 void WebContentsVideoCaptureDevice::AllocateAndStart(