Add/improve a bunch of comments...

chrome/browser/metrics/metrics_log.cc

 // Copyright (c) 2010 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/metrics/metrics_log.h"
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 80 matching lines @@
 
 void MetricsLog::RecordIncrementalStabilityElements() {
   DCHECK(!locked_);
 
   PrefService* pref = g_browser_process->local_state();
   DCHECK(pref);
 
   OPEN_ELEMENT_FOR_SCOPE("profile");
   WriteCommonEventAttributes();
 
-  WriteInstallElement();  // Supply appversion.
+  WriteInstallElement();
 
   {
     OPEN_ELEMENT_FOR_SCOPE("stability");  // Minimal set of stability elements.
     WriteRequiredStabilityAttributes(pref);
     WriteRealtimeStabilityAttributes(pref);
 
     WritePluginStabilityElements(pref);
   }
 }
 
@@ skipping 376 matching lines @@
       const std::string result_type(AutocompleteMatch::TypeToString(i->type));
       if (!result_type.empty())
         WriteAttribute("resulttype", result_type);
       WriteIntAttribute("relevance", i->relevance);
       WriteIntAttribute("isstarred", i->starred ? 1 : 0);
     }
   }
 
   ++num_events_;
 }