Plugin Power Saver: Add some UMAs to test plugins in wild.

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 2be9b0fa77878df0812d431ec613e54fa50c3f09..a1d5502e80d7b70dd111a175baf9156d0fd7361e 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -25072,6 +25072,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <summary>Collects Flash usage data.</summary>
 </histogram>
 
+<histogram name="Plugin.PowerSaverPeripheralHeuristic"
+    enum="PluginPowerSaverPeripheralHeuristicDecision">
+  <owner>tommycli@chromium.org</owner>
+  <summary>
+    Record initial decision of the Plugin Power Saver peripheral content
+    heuristic.

[Lei Zhang, 2014/11/05 22:32:56]

Mention this is per instance.

[tommycli, 2014/11/06 00:36:05]

Done.

+  </summary>
+</histogram>
+
 <histogram name="Plugin.PpapiBrokerLoadErrorCode" units="code">
   <owner>xhwang@chromium.org</owner>
   <summary>The error code of a PPAPI broker load failure.</summary>
@@ -51236,6 +51245,13 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="4" label="FILE_MISSING"/>
 </enum>
 
+<enum name="PluginPowerSaverPeripheralHeuristicDecision" type="int">
+  <int value="0" label="Peripheral"/>
+  <int value="1" label="Essential Same-Origin"/>
+  <int value="2" label="Essential Cross-Origin Big"/>
+  <int value="3" label="Essential Cross-Origin Whitelisted"/>

[Ilya Sherman, 2014/11/05 22:36:20]

These labels are a bit mysterious to me.  Perhaps you could expand the histogram
description to give a bit more of a hint of what the heuristic is doing?

[tommycli, 2014/11/06 00:36:05]

Done.

+</enum>
+
 <enum name="PNaClOptionsOptLevelEnum" type="int">
   <int value="0" label="0"/>
   <int value="1" label="1"/>