Track AsyncReadback time using histogram.

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 6a9a341b24d9552fb9ec5d7c0893f7428d193015..d85bc3fef3ff7b0eab6917b421583dc2bcf71895 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -12,6 +12,7 @@
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/worker_pool.h"
 #include "cc/base/latency_info_swap_promise.h"
@@ -90,10 +91,13 @@ void CopyFromCompositingSurfaceFinished(
     const base::Callback<void(bool, const SkBitmap&)>& callback,
     scoped_ptr<cc::SingleReleaseCallback> release_callback,
     scoped_ptr<SkBitmap> bitmap,
+    const base::TimeTicks& start_time,
     scoped_ptr<SkAutoLockPixels> bitmap_pixels_lock,
     bool result) {
   bitmap_pixels_lock.reset();
   release_callback->Run(0, false);
+  UMA_HISTOGRAM_TIMES("RWHVA.CopyFromCompositingSurface asyncreadback time",

[jar (doing other things), 2014/01/11 03:41:39]

nit: Did you intend to add data to the same histogram in line 1401?  If so, it
would be nicer to only list this long name once, such as in a small static
function (or in an anonymous namespace local to this file).

Also, for naming conventions for histograms:

What made you choose the prefix "RWHVA"?

Although not illegal, we usually don't have spaces in the histogram name (and it
is even stranger to mix BouncyCaps, combinednames, and spaces).

I'd suggest something like:

"Compositing.CopyFromSurfaceTime"

for the above histogram, and maybe for line 611:

"Compositing.CopyFromSurfaceTimeSynchronous"

[sivag, 2014/01/14 13:38:22]

Done.

+                      base::TimeTicks::Now() - start_time);
   callback.Run(result, *bitmap);
 }
 
@@ -585,6 +589,7 @@ void RenderWidgetHostViewAndroid::CopyFromCompositingSurface(
     const gfx::Rect& src_subrect,
     const gfx::Size& dst_size,
     const base::Callback<void(bool, const SkBitmap&)>& callback) {
+  base::TimeTicks start_time = base::TimeTicks::Now();
   if (!using_synchronous_compositor_ && !IsSurfaceAvailableForCopy()) {
     callback.Run(false, SkBitmap());
     return;
@@ -603,6 +608,8 @@ void RenderWidgetHostViewAndroid::CopyFromCompositingSurface(
 
   if (using_synchronous_compositor_) {
     SynchronousCopyContents(src_subrect_in_pixel, dst_size_in_pixel, callback);
+    UMA_HISTOGRAM_TIMES("RWHVA.SynchronousCopyContents",
+        base::TimeTicks::Now() - start_time);
     return;
   }
 
@@ -611,15 +618,18 @@ void RenderWidgetHostViewAndroid::CopyFromCompositingSurface(
       request = cc::CopyOutputRequest::CreateBitmapRequest(base::Bind(
           &RenderWidgetHostViewAndroid::PrepareBitmapCopyOutputResult,
           dst_size_in_pixel,
+          start_time,
           callback));
   } else {
       request = cc::CopyOutputRequest::CreateRequest(base::Bind(
           &RenderWidgetHostViewAndroid::PrepareTextureCopyOutputResult,
           dst_size_in_pixel,
+          start_time,
           callback));
   }
   request->set_area(src_subrect_in_pixel);
   layer_->RequestCopyOfOutput(request.Pass());
+

[jar (doing other things), 2014/01/11 03:41:39]

nit: no need for blank line

[sivag, 2014/01/14 13:38:22]

Done.

 }
 
 void RenderWidgetHostViewAndroid::CopyFromCompositingSurfaceToVideoFrame(
@@ -1315,6 +1325,7 @@ void RenderWidgetHostViewAndroid::OnLostResources() {
 // static
 void RenderWidgetHostViewAndroid::PrepareTextureCopyOutputResult(
     const gfx::Size& dst_size_in_pixel,
+    const base::TimeTicks& start_time,
     const base::Callback<void(bool, const SkBitmap&)>& callback,
     scoped_ptr<cc::CopyOutputResult> result) {
   DCHECK(result->HasTexture());
@@ -1361,12 +1372,14 @@ void RenderWidgetHostViewAndroid::PrepareTextureCopyOutputResult(
                  callback,
                  base::Passed(&release_callback),
                  base::Passed(&bitmap),
+                 start_time,
                  base::Passed(&bitmap_pixels_lock)));
 }
 
 // static
 void RenderWidgetHostViewAndroid::PrepareBitmapCopyOutputResult(
     const gfx::Size& dst_size_in_pixel,
+    const base::TimeTicks& start_time,
     const base::Callback<void(bool, const SkBitmap&)>& callback,
     scoped_ptr<cc::CopyOutputResult> result) {
   DCHECK(result->HasBitmap());
@@ -1385,6 +1398,9 @@ void RenderWidgetHostViewAndroid::PrepareBitmapCopyOutputResult(
   DCHECK_EQ(source->height(), dst_size_in_pixel.height());
 
   ignore_result(scoped_callback_runner.Release());
+  UMA_HISTOGRAM_TIMES("RWHVA.CopyFromCompositingSurface asyncreadback time",
+                      base::TimeTicks::Now() - start_time);
+
   callback.Run(true, *source);
 }