Introduce ActiveScriptController; track active extension scripts

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 069d89a401a970044e34d1906b6615c2b6f60aef..97b572ade1b5c3b068b9a2fb9e23a4eb235396ce 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -5725,6 +5725,40 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Extensions.ActiveScriptController.PreventableAdInjectors"
+    units="Extension Count">
+  <owner>kalman@chromium.org</owner>
+  <owner>rdevlin.cronin@chromium.org</owner>
+  <summary>
+    The number of extensions per page that injected an ad and could have been
+    stopped if the user had declined script injection. This is related to the
+    ActivityLog metrics, ExtensionActivity.Ad*. Recorded upon page close or
+    navigation.
+  </summary>
+</histogram>
+
+<histogram name="Extensions.ActiveScriptController.ShownActiveScriptsOnPage"
+    units="Number of Actions">
+  <owner>kalman@chromium.org</owner>
+  <owner>rdevlin.cronin@chromium.org</owner>
+  <summary>
+    The number of extensions which would display an Active Script Running
+    indiciation to the user. Recorded at page close.
+  </summary>
+</histogram>
+
+<histogram name="Extensions.ActiveScriptController.UnpreventableAdInjectors"
+    units="Extension Count">
+  <owner>kalman@chromium.org</owner>
+  <owner>rdevlin.cronin@chromium.org</owner>
+  <summary>
+    The number of extensions per page that injected an ad and that could not
+    have been stopped through script injection permission. This is related to
+    the ActivityLog metrics, ExtensionActivity.Ad*. Recorded upon page close or
+    navigation.
+  </summary>
+</histogram>
+
 <histogram name="Extensions.AllocatePortIdPairOverflow">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <summary>
@@ -7053,6 +7087,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="FileBrowser.VolumeType" enum="FileManagerVolumeType">
+  <owner>kinaba@chromium.org</owner>
+  <summary>
+    Chrome OS File Browser: counts the number of times volumes are mounted for
+    each volume type.
+  </summary>
+</histogram>
+
 <histogram name="GCM.APICallUnregister">
   <owner>jianli@chromium.org</owner>
   <summary>Number of times when gcm.unregister API is called.</summary>
@@ -7067,14 +7109,6 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
-<histogram name="FileBrowser.VolumeType" enum="FileManagerVolumeType">
-  <owner>kinaba@chromium.org</owner>
-  <summary>
-    Chrome OS File Browser: counts the number of times volumes are mounted for
-    each volume type.
-  </summary>
-</histogram>
-
 <histogram name="GCM.CheckinRequestStatus" enum="GCMCheckinRequestStatus">
   <owner>juyik@chromium.org</owner>
   <summary>Status code of the outcome of a GCM checkin request.</summary>