Update histograms.xml for recent Blink UseCounter addition.

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 16874 matching lines @@
   <int value="12" label="LegacyTextNotifications"/>
   <int value="13" label="UnprefixedRequestAnimationFrame"/>
   <int value="14" label="PrefixedRequestAnimationFrame"/>
   <int value="15" label="ContentSecurityPolicy"/>
   <int value="16" label="ContentSecurityPolicyReportOnly"/>
   <int value="17" label="PrefixedContentSecurityPolicyReportOnly"/>
   <int value="18" label="PrefixedTransitionEndEvent"/>
   <int value="19" label="UnprefixedTransitionEndEvent"/>
   <int value="20" label="PrefixedAndUnprefixedTransitionEndEvent"/>
   <int value="21" label="AutoFocusAttribute"/>
-  <int value="22" label="DeprecatedAutoSaveAttribute"/>
+  <int value="22" label="SVGAnimationElement"/>

[Ilya Sherman, 2013/07/26 01:20:30]

Hmm, why did this enum value change?  Was it wrong before?  If not, this change
will make it hard to make sense of data on the dashboard, as there will be
conflicting meanings for this enum value depending on the version of Chrome
that's uploading the data :(

[tkent, 2013/07/26 01:38:41]

Hmm, counting SVGAnimationElement started on July 11.  Only Canary and Dev have
it. We can change the enum value.

   <int value="23" label="DataListElement"/>
   <int value="24" label="FormAttribute"/>
   <int value="25" label="IncrementalAttribute"/>
   <int value="26" label="InputTypeColor"/>
   <int value="27" label="InputTypeDate"/>
   <int value="28" label="InputTypeDateTime"/>
   <int value="29" label="InputTypeDateTimeFallback"/>
   <int value="30" label="InputTypeDateTimeLocal"/>
   <int value="31" label="InputTypeEmail"/>
   <int value="32" label="InputTypeMonth"/>
@@ skipping 11 matching lines @@
   <int value="44" label="PatternAttribute"/>
   <int value="45" label="PlaceholderAttribute"/>
   <int value="46" label="PrecisionAttribute"/>
   <int value="47" label="PrefixedDirectoryAttribute"/>
   <int value="48" label="PrefixedSpeechAttribute"/>
   <int value="49" label="RequiredAttribute"/>
   <int value="50" label="ResultsAttribute"/>
   <int value="51" label="StepAttribute"/>
   <int value="52" label="PageVisits"/>
   <int value="53" label="HTMLMarqueeElement"/>
-  <int value="54" label="CSSOverflowMarquee"/>
+  <int value="54" label="Unused: CSSOverflowMarquee"/>
   <int value="55" label="Reflection"/>
   <int value="56" label="CursorVisibility"/>
   <int value="57" label="StorageInfo"/>
   <int value="58" label="XFrameOptions"/>
   <int value="59" label="XFrameOptionsSameOrigin"/>
   <int value="60" label="XFrameOptionsSameOriginWithBadAncestorChain"/>
   <int value="61" label="DeprecatedFlexboxWebContent"/>
   <int value="62" label="DeprecatedFlexboxChrome"/>
   <int value="63" label="DeprecatedFlexboxChromeExtension"/>
   <int value="64" label="SVGTRefElement"/>
   <int value="65" label="UnprefixedPerformanceTimeline"/>
   <int value="66" label="PrefixedPerformanceTimeline"/>
   <int value="67" label="UnprefixedUserTiming"/>
   <int value="68" label="PrefixedUserTiming"/>
   <int value="69" label="WindowEvent"/>
   <int value="70" label="ContentSecurityPolicyWithBaseElement"/>
   <int value="71" label="PrefixedMediaAddKey"/>
   <int value="72" label="PrefixedMediaGenerateKeyRequest"/>
   <int value="73" label="WebAudioLooping"/>
   <int value="74" label="DocumentClear"/>
   <int value="75" label="PrefixedTransitionMediaFeature"/>
   <int value="76" label="SVGFontElement"/>
   <int value="77" label="XMLDocument"/>
   <int value="78" label="XSLProcessingInstruction"/>
   <int value="79" label="XSLTProcessor"/>
+  <int value="80" label="SVGSwitchElement"/>
+  <int value="81" label="PrefixedDocumentRegister"/>
+  <int value="82" label="HTMLShadowElementOlderShadowRoot"/>
+  <int value="83" label="Document.all()"/>
+  <int value="84" label="FormElement"/>
+  <int value="85" label="DemotedFormElement"/>
+  <int value="86" label="CaptureAttributeAsEnum"/>
+  <int value="87" label="ShadowDOMPrefixedPseudo"/>
+  <int value="88" label="ShadowDOMPrefixedCreateShadowRoot"/>
+  <int value="89" label="ShadowDOMPrefixedShadowRoot"/>
 </enum>
 
 <enum name="FFmpegCodecs" type="int">
   <int value="0" label="NONE"/>
   <int value="1" label="MPEG1VIDEO"/>
   <int value="2" label="MPEG2VIDEO"/>
   <int value="3" label="MPEG2VIDEO_XVMC"/>
   <int value="4" label="H261"/>
   <int value="5" label="H263"/>
   <int value="6" label="RV10"/>
@@ skipping 6593 matching lines @@
   <group name="Disabled" label="Neither extra webstore link is visible"/>
   <group name="FooterLink" label="Link in bottom right of footer"/>
   <group name="PlusIcon" label="Plus icon in apps page"/>
   <affected-histogram name="Extensions.AppLaunch"/>
   <affected-histogram name="NewTabPage.DefaultPageType"/>
 </fieldtrial>
 
 </fieldtrials>
 
 </histogram-configuration>