Add UMA histograms for DirectComposition overlays.

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 630dcc9c3eab85be0429371d4727c2ab88df9179..bd0caf1f80e3222e5c428fee8a08a982d73ed6e2 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -21668,6 +21668,26 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="GPU.DirectComposition.CompositionMode"
+    enum="DxgiFramePresentationMode">
+  <owner>jbauman@chromium.org</owner>
+  <summary>
+    How the Desktop Window Manager presented Chrome's DirectComposition layers
+    to the screen.
+  </summary>
+</histogram>
+
+<histogram name="GPU.DirectComposition.OverlaysSupported"
+    enum="BooleanOverlaySupported">
+  <owner>jbauman@chromium.org</owner>
+  <summary>True if Chrome will try to use DirectComposition overlays.</summary>
+</histogram>
+
+<histogram name="GPU.DirectComposition.OverlaysUsed" enum="BooleanOverlayUsage">
+  <owner>jbauman@chromium.org</owner>
+  <summary>Whether or not a frame displays an overlay.</summary>
+</histogram>
+
 <histogram name="GPU.DoLinkProgramTime" units="ms">
   <owner>jmadill@chromium.org</owner>
   <summary>
@@ -83711,6 +83731,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Orphan"/>
 </enum>
 
+<enum name="BooleanOverlaySupported" type="int">
+  <int value="0" label="No overlays supported"/>
+  <int value="1" label="Supports overlays"/>
+</enum>
+
+<enum name="BooleanOverlayUsage" type="int">
+  <int value="0" label="No overlay"/>
+  <int value="1" label="Overlay"/>
+</enum>
+
 <enum name="BooleanPanelWasOpen" type="int">
   <int value="0" label="Panel was closed"/>
   <int value="1" label="Panel was open"/>
@@ -88794,6 +88824,13 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="2" label="Unknown"/>
 </enum>
 
+<enum name="DxgiFramePresentationMode" type="int">
+  <int value="0">Composed</int>
+  <int value="1">Overlay</int>
+  <int value="2">None (Unknown)</int>
+  <int value="3">Composition Failure</int>
+</enum>
+
 <enum name="EAPInnerProtocol" type="int">
   <int value="0" label="UNKNOWN"/>
   <int value="1" label="NONE"/>