Adds UMA for display color calibration in ChromeOS.

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 7f449f5a0f258795861a456fbee1468e2ab2668f..81a8757c15122146bab42154458f9b01d6469082 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -2035,6 +2035,14 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="ChromeOS.Display.ColorProfile" enum="ChromeOSColorProfile">
+  <owner>xiaowenx@chromium.org</owner>
+  <owner>mukai@chromium.org</owner>
+  <summary>
+    The name of the color calibration of the display on ChromeOS.

[Alexei Svitkine (slow), 2014/03/26 13:02:10]

Can you mention when this is logged? On user login? On device startup? Only when
it changes?

[Jun Mukai, 2014/03/26 18:08:09]

added.

+  </summary>
+</histogram>
+
 <histogram name="ChromeOS.SAML.APIUsed" enum="BooleanUsage">
   <owner>bartfab@chromium.org</owner>
   <summary>
@@ -29899,6 +29907,14 @@ other types of suffix sets.
   <int value="2" label="First service disabled"/>
 </enum>
 
+<enum name="ChromeOSColorProfile" type="int">
+  <summary>See ui/display/display_constants.h for the variation.</summary>
+  <int value="0" label="Standard"/>
+  <int value="1" label="Dynamic"/>
+  <int value="2" label="Movie"/>
+  <int value="3" label="Reading"/>
+</enum>
+
 <enum name="ChromeOSUserImageId" type="int">
   <summary>
     Indices of the default images as defined in