Add UMA for navigator.permissions.query() usage.

Has to land after Blink CL: https://codereview.chromium.org/1057193003/

BUG=474692

Review URL: https://codereview.chromium.org/1059563005

Cr-Commit-Position: refs/heads/master@{#324166}

tools/metrics/histograms/histograms.xml

@@ -51305,6 +51305,7 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="746" label="TabStopProperty"/>
   <int value="747" label="TabStopAttribute"/>
   <int value="748" label="LegacyConst"/>
+  <int value="750" label="V8Permissions_Query_Method"/>
 </enum>
 
 <enum name="FFmpegCodecs" type="int">