tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 9dab252cb5b8ab5b8fb5b5d8f885396e16afd2c8..347421193ba1c203e3d56d7d95e069cb8153f7f1 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -8024,6 +8024,30 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Compositing.SurfaceAggregator.SurfaceDrawQuad.NoActiveFrame">
+  <owner>kylechar@chromium.org</owner>
+  <summary>
+    The number of SurfaceDrawQuads where the surface exists but doesn't have an
+    active CompositorFrame. This is logged for one call to Aggregate().

[jwd, 2017/03/21 14:07:31]

Hm, can you change "one" to "each" for these summaries or is it not every call?
If it's not every call, can you be more specific about what call it is logged.

[kylechar, 2017/03/21 14:22:53]

Done.

+  </summary>
+</histogram>
+
+<histogram name="Compositing.SurfaceAggregator.SurfaceDrawQuad.SurfaceMissing">
+  <owner>kylechar@chromium.org</owner>
+  <summary>
+    The number of SurfaceDrawQuads where the surface doesn't exist. This is
+    logged for one call to Aggregate().
+  </summary>
+</histogram>
+
+<histogram name="Compositing.SurfaceAggregator.SurfaceDrawQuad.ValidSurface">

[jwd, 2017/03/21 14:07:31]

Note, you could have used histogram suffixes for these, and saved some precious
precious XML. The change is optional and I don't mind if you don't, but keep it
in mind for future histograms.

[kylechar, 2017/03/21 14:22:53]

I'll definitely keep that in mind.

+  <owner>kylechar@chromium.org</owner>
+  <summary>
+    The number of SurfaceDrawQuads where the surface exists and has an active
+    CompositorFrame. This is logged for one call to Aggregate().
+  </summary>
+</histogram>
+
 <histogram name="Conflicts.ConfirmedBadModules" units="modules">
   <owner>chrisha@chromium.org</owner>
   <summary>