Media Galleries: Add a dropPermissionForMediaFileSystem() API.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
===================================================================
--- tools/metrics/histograms/histograms.xml	(revision 262440)
+++ tools/metrics/histograms/histograms.xml	(working copy)
@@ -32970,6 +32970,13 @@
   <int value="707" label="BLUETOOTHPRIVATE_ENABLEPAIRING"/>
   <int value="708" label="BLUETOOTHPRIVATE_DISABLEPAIRING"/>
   <int value="709" label="BLUETOOTHPRIVATE_SETPAIRINGRESPONSE"/>
+  <int value="710" label="NETWORKINGPRIVATE_GETCAPTIVEPORTALSTATUS"/>
+  <int value="711" label="AUTOMATIONINTERNAL_PERFORMACTION"/>
+  <int value="712" label="BLUETOOTH_UPDATE_SOCKET"/>
+  <int value="713" label="BLUETOOTH_SET_SOCKET_PAUSED"/>
+  <int value="714" label="BLUETOOTH_GET_SOCKET"/>
+  <int value="715" label="BLUETOOTH_GET_SOCKETS"/>
+  <int value="716" label="MEDIAGALLERIES_DROPPERMISSIONFORMEDIAFILESYSTEM"/>
 </enum>
 
 <enum name="ExtensionInstallCause" type="int">
@@ -36185,6 +36192,7 @@
   <int value="19" label="AddScanResults dialog accepted"/>
   <int value="20" label="Gallery removed from AddScanResults dialog"/>
   <int value="21" label="Gallery removed from permission dialog"/>
+  <int value="22" label="DropPermissionForMediaFileSystem API invocations"/>
 </enum>
 
 <enum name="MediaKeyError" type="int">