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

chrome/browser/content_settings/content_settings_pref_provider.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/content_settings/content_settings_pref_provider.h"
 
 #include <string>
 #include <utility>
 #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/prefs/pref_service.h"
 #include "chrome/browser/prefs/scoped_user_pref_update.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/content_settings.h"
 #include "chrome/common/pref_names.h"
 #include "content/browser/browser_thread.h"
 #include "content/browser/user_metrics.h"
@@ skipping 343 matching lines @@
   }
   if (prefs->GetInteger(prefs::kContentSettingsVersion) >
       ContentSettingsPattern::kContentSettingsPatternVersion) {
     LOG(ERROR) << "Unknown content settings version in preferences.";
     return;
   }
 
   // Read exceptions.
   ReadExceptions(false);
 
+  if (!is_incognito()) {
+    UMA_HISTOGRAM_COUNTS("ContentSettings.NumberOfExceptions",

[jar (doing other things), 2011/05/25 02:19:50]

One thing to test is to be sure the histogram system is initialized before you
record this data. 

To test: Start up the browser, and then visit:
about:histograms/ContentSettings.NumberOfExceptions

IF you see data, then everything is fine.  If you don't, then we'll need to work
a bit harder.  The histogram system is initialized pretty early.... but you
should check.

+                         host_content_settings()->size());
+  }
+
   pref_change_registrar_.Init(prefs);
   pref_change_registrar_.Add(prefs::kContentSettingsPatterns, this);
 
   notification_registrar_.Add(this, NotificationType::PROFILE_DESTROYED,
                               Source<Profile>(profile_));
   initializing_ = false;
 }
 
 void PrefProvider::SetContentSetting(
     const ContentSettingsPattern& requesting_pattern,
@@ skipping 442 matching lines @@
                         ContentSettingsPattern::FromString(host),
                         CONTENT_SETTINGS_TYPE_POPUPS,
                         "",
                         CONTENT_SETTING_ALLOW);
     }
     prefs->ClearPref(prefs::kPopupWhitelistedHosts);
   }
 }
 
 }  // namespace content_settings