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 694c7ad2c189cdb67d4c7188b4f2fb7f3fb685e4..2a260a28548defda3a5dd099f974849c22e5ac41 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -4103,6 +4103,237 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="Event.Latency.Renderer2" units="microseconds">
+  <summary>
+    Time between initiation of all input events and renderer processing. This
+    supersedes the earlier Event.Latency.Renderer metric.

[jar (doing other things), 2014/01/18 02:44:48]

Rather than putting "supersedes" in here, and referencing outdated histograms,
it is probably better to put the relationship in the old histogram, encouraging
folks to look to the new one.

As you noted, you didn't (yet) want to use the obsolete tag in the old... but
you can at least add a reference.

Removing these repetitious prose-lines will also make this a much more compact
change (of new stuff).

It is also tempting to pull out the common prose, and a common prefix, and use a
<field_trial> tag to list the details.

As you have written this CL, you used the same description in almost all your
histograms, which makes the prose rather useless.  For example, I have *no* idea
what your Reneder2.Char is talking about, as I don't know what a "Char" event
is.  The goal is to make the prose be more self explanatory, and hence generally
specific.

IMO, it would be better to have this (overall) histogram named differently, or
have a different postfix, like:
Event.Latency.Renderer2.AllInputEventsCombined
or possible better (so you can use the field_trial tricks):
Event.LatencyCombined.Renderer2

You can then have just the prefix histogram defined:
Event.Latency.Render2
with *clearer* common prose, and then use field trial to define the extensions:
Char
ContextMenue
GestureDoubleTap
GestureFlingCancel
...

along with clear and distinctive prose elaborating the meaning in each case.

+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.Char" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.Char metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.ContextMenu" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.ContextMenu metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureDoubleTap" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureDoubleTap metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureFlingCancel"
+    units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureFlingCancel metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureFlingStart"
+    units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureFlingStart metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureLongPress" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureLongPress metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureLongTap" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureLongTap metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GesturePinchBegin"
+    units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GesturePinchBegin metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GesturePinchEnd" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GesturePinchEnd metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GesturePinchUpdate"
+    units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GesturePinchUpdate metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureScrollBegin"
+    units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureScrollBegin metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureScrollEnd" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureScrollEnd metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureScrollUpdate"
+    units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureScrollUpdate metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureTap" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureTap metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureTapCancel" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.RendererGestureTapCancel metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureTapDown" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureTapDown metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.GestureTwoFingerTap"
+    units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.GestureTwoFingerTap metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.KeyDown" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.KeyDown metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.KeyUp" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.KeyUp metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.MouseDown" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.MouseDown metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.MouseEnter" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.MouseEnter metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.MouseLeave" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.MouseLeave metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.MouseMove" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.MouseMove metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.MouseUp" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.MouseUp metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.MouseWheel" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.MouseWheel metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.RawKeyDown" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.RawKeyDown metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.TouchCancel" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.TouchCancel metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.TouchEnd" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.TouchEnd metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.TouchMove" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.TouchMove metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.TouchStart" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.TouchStart metric.
+  </summary>
+</histogram>
+
+<histogram name="Event.Latency.Renderer2.Undefined" units="microseconds">
+  <summary>
+    Time between initiation of input event and browser processing. This
+    supersedes the earlier Event.Latency.Renderer.Undefined metric.
+  </summary>
+</histogram>
+
 <histogram name="Event.Latency.RendererImpl.GestureScroll" units="microseconds">
   <obsolete>
     Deprecated 12/2013 and replaced by Event.Latency.RendererImpl.GestureScroll2