Add a histogram for the number of hostname patterns for content settings

BUG=83825
TEST=none


Review URL: http://codereview.chromium.org/7008004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@86641 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/content_settings/content_settings_pref_provider.cc

@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "base/command_line.h"
+#include "base/metrics/histogram.h"
 #include "chrome/browser/content_settings/content_settings_details.h"
 #include "chrome/browser/content_settings/content_settings_pattern.h"
 #include "chrome/browser/content_settings/content_settings_utils.h"
@@ -372,6 +373,11 @@ void PrefProvider::Init() {
   // Read exceptions.
   ReadExceptions(false);
 
+  if (!is_incognito()) {
+    UMA_HISTOGRAM_COUNTS("ContentSettings.NumberOfExceptions",
+                         host_content_settings()->size());
+  }
+
   pref_change_registrar_.Init(prefs);
   pref_change_registrar_.Add(prefs::kContentSettingsPatterns, this);