Add a UMA metric for whenever an extension is wiped out and when it gets re-enabled.

TBR=sky (for OWNERS)
BUG=154624
TEST=None, the UMA experiment dashboard needs to be checked to see the new boolean histogram.
Review URL: https://codereview.chromium.org/11416033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@168502 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index 872a9ee..d8eb7d6 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -926,6 +926,10 @@
     AcknowledgeExternalExtension(extension->id());
   }
 
+  if (extension_prefs_->GetDisableReasons(extension->id()) &
+      Extension::DISABLE_SIDELOAD_WIPEOUT)
+    UMA_HISTOGRAM_BOOLEAN("DisabledExtension.ExtensionWipedStatus", false);
+
   // Move it over to the enabled list.
   extensions_.Insert(make_scoped_refptr(extension));
   disabled_extensions_.Remove(extension->id());
@@ -2254,6 +2258,7 @@
           extension->id(),
           static_cast<Extension::DisableReason>(
           Extension::DISABLE_SIDELOAD_WIPEOUT));
+      UMA_HISTOGRAM_BOOLEAN("DisabledExtension.ExtensionWipedStatus", true);
     }
   }
 }