Create a field trial to test if we can detect good QPC implementations.

tools/metrics/histograms/histograms.xml

 <!--
 Copyright 2013 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
 <!--
 This file is used to generate a comprehensive list of Chrome histograms along
 with a detailed description for each histogram.
 
@@ skipping 388 matching lines @@
 </histogram>
 
 <histogram name="RequestAutocomplete.WalletRequiredActions"
     enum="WalletRequiredActions">
   <summary>
     Measures the frequency of required user actions returned by the Google
     Online Wallet server.
   </summary>
 </histogram>
 
+<histogram name="WinTimeTicks.ChangedCores" enum="WindowsVersion">
+  <summary>
+    Incremented each time the TimeTicks field trial completes and switched cores
+    at least once. Broken down by Windows version.
+  </summary>
+</histogram>
+
+<histogram name="WinTimeTicks.MinResolutionNanoseconds" units="microseconds">

[jar (doing other things), 2013/04/12 02:14:54]

nit: units should be nanoseconds

[James Simonsen, 2013/04/12 02:29:46]

Doh. Fixed.

+  <summary>
+    The smallest non-zero delta reported by subsequent calls to
+    QueryPerformanceCounter.
+  </summary>
+</histogram>
+
+<histogram name="WinTimeTicks.NonDecreasing" enum="WindowsVersion">
+  <summary>
+    The number of times the TimeTicks field trial reported non-decreasing
+    QueryPerformanceCounter values. Broken down by Windows version.
+  </summary>
+</histogram>
+
+<histogram name="WinTimeTicks.NonStopTsc">
+  <summary>
+    True if the CPU's time stamp counter ticks at a constant rate regardless of
+    CPU frequency.
+  </summary>
+</histogram>
+
+<histogram name="WinTimeTicks.VersionSuccessful" enum="WindowsVersion">
+  <summary>
+    The number of times the TimeTicks field trial succeeded. Broken down by
+    Windows version.
+  </summary>
+</histogram>
+
+<histogram name="WinTimeTicks.VersionTotal" enum="WindowsVersion">
+  <summary>
+    The number of times the TimeTicks field trial ran for comparison with
+    WinTimeTicks.VersionSuccess. Broken down by Windows version.
+  </summary>
+</histogram>
+
 </histograms>
 
 <!-- Enum types -->
 
 <enums>
 
 <enum name="AutocheckoutBubble" type="int">
   <int value="0" label="Created"/>
   <int value="1" label="Accepted"/>
   <int value="2" label="Dismissed"/>
@@ skipping 931 matching lines @@
   <int value="4" label="Set up Wallet"/>
   <int value="5" label="Accept ToS"/>
   <int value="6" label="Update expiration date"/>
   <int value="7" label="Upgrade min address"/>
   <int value="8" label="Choose another instrument or address"/>
   <int value="9" label="Verify CVV"/>
   <int value="10" label="Invalid form field"/>
   <int value="11" label="Require phone number"/>
 </enum>
 
+<enum name="WindowsVersion" type="int">
+  <int value="0" label="Pre-XP"/>
+  <int value="1" label="XP"/>
+  <int value="2" label="2003 Server"/>
+  <int value="3" label="Vista"/>
+  <int value="4" label="7"/>

[jar (doing other things), 2013/04/12 02:14:54]

nit: probably "Windows 7" would be better (so it doesn't look like you didn't
put in a label... and it is displaying a number).

Same thing for "8"

[James Simonsen, 2013/04/12 02:29:46]

Done.

+  <int value="5" label="8"/>
+</enum>
+
 </enums>
 
 <!-- Field trials -->
 
 <fieldtrials>
 
 <fieldtrial name="AutofillServerExperiments">
   <group name="ar06" label="Acceptance ratio: 0.6"/>
   <group name="ar1" label="Acceptance ratio: 1.0"/>
   <group name="ar2" label="Acceptance ratio: 2.0"/>
@@ skipping 28 matching lines @@
   <affected-histogram name="Autofill.Quality.HeuristicType.ByFieldType"/>
   <affected-histogram name="Autofill.Quality.PredictedType"/>
   <affected-histogram name="Autofill.Quality.PredictedType.ByFieldType"/>
   <affected-histogram name="Autofill.Quality.ServerType"/>
   <affected-histogram name="Autofill.Quality.ServerType.ByFieldType"/>
 </fieldtrial>
 
 </fieldtrials>
 
 </histogram-configuration>