Finalize new UseCounter histogram names

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 994c4a276cae418a41ef764b699a9d4b3348e358..4c29c3f7248a19cec7f2e8fe69f6809519915809 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -4512,6 +4512,80 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Blink.UseCounter.CSSProperties" enum="MappedCSSProperties">
+  <owner>rbyers@chromium.org</owner>
+  <summary>
+    Records usage of CSS properties used on a page, either statically or
+    dynamically, from the time the page is initialised to when it is closed or
+    navigated away from. Each property is counted at most once per page per
+    view.
+  </summary>
+  <details>
+    The first time a CSS property is parsed on a page, the histogram is updated
+    to increment the counter.  Each histogram bucket corresponds to a CSS
+    property (eg. width, border-radius). The exception is the 'Total pages
+    measured' bucket - this counts the number of pages that CSS properties were
+    counted on.  When a page navigation occurs the page count bucket is
+    incremented and tracking of the set of which properties have been seen is
+    reset.
+
+    These numbers give the percentage of pages that use a CSS property. For
+    example, if the 'border-radius' histogram bucket has a count of 250, and the
+    page count bucket (i.e. bucket number 1) has a count of 1000 - this means
+    that 1000 pages were recorded, and border-radius was used on 25% of those
+    pages.
+
+    Note that CSS properties used inside of SVG images are tracked separately in
+    the Blink.UseCounter.SVGImage.CSSProperties histogram.
+
+    As of M57 this histogram supercedes WebCore.FeatureObserver.CSSProperties.
+  </details>
+</histogram>
+
+<histogram name="Blink.UseCounter.Features" enum="FeatureObserver">
+  <owner>rbyers@chromium.org</owner>
+  <summary>
+    Count of how many page loads use various features. The PageVisits bucket is
+    incremented for each page load, and the other buckets incremented at most
+    once per PageVisit via the WebCore::UseCounter class.
+  </summary>
+  <details>
+    Note that features used inside of SVG images are tracked separately in the
+    Blink.UseCounter.SVGImage.Features histogram.
+
+    As of M57 this histograms supercedes WebCore.FeatureObserver.
+  </details>
+</histogram>
+
+<histogram name="Blink.UseCounter.SVGImage.CSSProperties"
+    enum="MappedCSSProperties">
+  <owner>rbyers@chromium.org</owner>
+  <summary>
+    Like Blink.UseCounter.CSSProperties but specifically for the case of CSS
+    properties used inside of an SVG image.
+  </summary>
+  <details>
+    The 'Total pages measured' bucket is incremented each time a new SVG image
+    is created.  Note that the same SVG image can be used across multiple tabs
+    in a single renderer but this counts as a single usage. See
+    http://crbug.com/236262.
+  </details>
+</histogram>
+
+<histogram name="Blink.UseCounter.SVGImage.Features" enum="FeatureObserver">
+  <owner>rbyers@chromium.org</owner>
+  <summary>
+    Like Blink.UseCounter.Features except specifically for the case of SVG
+    Images.
+  </summary>
+  <details>
+    Count of how many SVG images use various features. The PageVisits bucket is
+    incremented each time a new SVG image is created.  Note that the same SVG
+    image can be used across multiple tabs in a single renderer but this counts
+    as a single usage.  See http://crbug.com/236262.
+  </details>
+</histogram>
+
 <histogram name="Blink.XHR.setRequestHeader.HeaderValueCategoryInRFC7230"
     enum="XMLHttpRequestHeaderValueCategoryInRFC7230">
   <owner>hiroshige@chromium.org</owner>
@@ -72152,9 +72226,8 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 <histogram name="WebCore.FeatureObserver" enum="FeatureObserver">
   <owner>rbyers@chromium.org</owner>
   <summary>
-    NOTE: This is in the process of being superseded by
-    WebCore.UseCounter.Features which fixes a number of issues.  See
-    https://crbug.com/597963.
+    NOTE: As of M57 this has been superseded by Blink.UseCounter.Features which
+    fixes a number of issues.  See https://crbug.com/676837.
 
     Count of how many page loads use various features. The PageVisits bucket is
     incremented for each page load, and the other buckets incremented at most
@@ -72166,9 +72239,8 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
     enum="MappedCSSProperties">
   <owner>mikelawther@chromium.org</owner>
   <summary>
-    NOTE: This is in the process of being superseded by
-    WebCore.UseCounter.CSSProperties which fixes a number of issues.  See
-    https://crbug.com/597963.
+    NOTE: As of M57 this has been superseded by Blink.UseCounter.Features which
+    fixes a number of issues.  See https://crbug.com/676837.
 
     Records usage of CSS properties used on a page, either statically or
     dynamically, from the time the page is initialised to when it is closed or
@@ -72750,81 +72822,33 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="WebCore.UseCounter_TEST.CSSProperties"
     enum="MappedCSSProperties">
+  <obsolete>
+    Temporary histogram replaced by Blink.UseCounter.CSSProperties.
+  </obsolete>
   <owner>rbyers@chromium.org</owner>
-  <summary>
-    NOTE: This is in the process of replacing
-    WebCore.FeatureObserver.CSSProperties which fixes a number of issues.  See
-    https://crbug.com/597963.
-
-    Records usage of CSS properties used on a page, either statically or
-    dynamically, from the time the page is initialised to when it is closed or
-    navigated away from. Each property is counted at most once per page per
-    view.
-  </summary>
-  <details>
-    The first time a CSS property is parsed on a page, the histogram is updated
-    to increment the counter.  Each histogram bucket corresponds to a CSS
-    property (eg. width, border-radius). The exception is the 'Total pages
-    measured' bucket - this counts the number of pages that CSS properties were
-    counted on.  When a page navigation occurs the page count bucket is
-    incremented and tracking of the set of which properties have been seen is
-    reset.
-
-    These numbers give the percentage of pages that use a CSS property. For
-    example, if the 'border-radius' histogram bucket has a count of 250, and the
-    page count bucket (i.e. bucket number 1) has a count of 1000 - this means
-    that 1000 pages were recorded, and border-radius was used on 25% of those
-    pages.
-
-    TODO: The exact definition of &quot;page load&quot; is still
-    incorrect/fuzzy. https://crbug.com/236262
-  </details>
 </histogram>
 
 <histogram name="WebCore.UseCounter_TEST.Features" enum="FeatureObserver">
+  <obsolete>
+    Temporary histogram replaced by Blink.UseCounter.Features.
+  </obsolete>
   <owner>rbyers@chromium.org</owner>
-  <summary>
-    NOTE: This is in the process of replacing WebCore.FeatureObserver which
-    fixes a number of issues.  See https://crbug.com/597963.
-
-    Count of how many page loads use various features. The PageVisits bucket is
-    incremented for each page load, and the other buckets incremented at most
-    once per PageVisit via the WebCore::UseCounter class.
-  </summary>
-  <details>
-    TODO: The exact definition of &quot;page load&quot; is still
-    incorrect/fuzzy. https://crbug.com/236262
-  </details>
 </histogram>
 
 <histogram name="WebCore.UseCounter_TEST.SVGImage.CSSProperties"
     enum="MappedCSSProperties">
+  <obsolete>
+    Temporary histogram replaced by Blink.UseCounter.SVGImage.CSSProperties.
+  </obsolete>
   <owner>rbyers@chromium.org</owner>
-  <summary>
-    Like WebCore.UseCounter_TEST.CSSProperties but specifically for the case of
-    CSS properties used inside of an SVG image.
-  </summary>
-  <details>
-    The 'Total pages measured' bucket is incremented each time a new SVG image
-    is created.  Note that the same SVG image can be used across multiple tabs
-    in a single renderer but this counts as a single usage. See
-    http://crbug.com/236262.
-  </details>
 </histogram>
 
 <histogram name="WebCore.UseCounter_TEST.SVGImage.Features"
     enum="FeatureObserver">
+  <obsolete>
+    Temporary histogram replaced by Blink.UseCounter.SVGImage.Features.
+  </obsolete>
   <owner>rbyers@chromium.org</owner>
-  <summary>
-    Like WebCore.UseCounter_TEST.Features except specifically for the case of
-    SVG Images.
-  </summary>
-  <details>
-    Count of how many SVG images use various features. The PageVisits bucket is
-    incremented each time a new SVG image is created.  Note that the same SVG
-    image can be used across multiple tabs in a single renderer but this counts
-    as a single usage.  See http://crbug.com/236262.
-  </details>
 </histogram>
 
 <histogram name="WebCore.V8DOMWindowShell.createContext.IsolatedWorld"