Enable win32k lockdown for ppapi processes.

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 7b1b06fab4963a559caf172ea129f398387cbaeb..c041f4d7ea5d544ce7c42cb1807339f1a194df74 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -70992,6 +70992,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Windows.Win32kRendererLockdown" enum="BooleanEnabled">
+  <obsolete>
+    Deprecated 10/2016 as this is enabled by default so provides no useful data.
+  </obsolete>
   <owner>wfh@chromium.org</owner>
   <summary>
     Count of browser launches where Win32k renderer lockdown is enabled.
@@ -88711,6 +88714,7 @@ value.
   <int value="368854020" label="ash-screen-rotation-animation"/>
   <int value="370486304" label="enable-origin-chip-on-srp"/>
   <int value="379326303" label="enable-add-to-shelf"/>
+  <int value="385969127" label="disable-win32k-lockdown"/>
   <int value="400322063" label="ash-disable-screen-orientation-lock"/>
   <int value="401983950" label="enable-spdy4"/>
   <int value="402143634" label="enable-search-button-in-omnibox-always"/>