Memory save on some OmniBox histograms.

chrome/browser/prerender/prerender_histograms.cc

 // Copyright (c) 2012 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/prerender/prerender_histograms.h"
 
 #include <string>
 
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
@@ skipping 132 matching lines @@
   // If we observe multiple tags within the 30 second window, we will still
   // reset the window to begin at the most recent occurrence, so that we will
   // always be in a window in the 30 seconds from each occurrence.
   last_prerender_seen_time_ = GetCurrentTimeTicks();
   seen_any_pageload_ = false;
   seen_pageload_started_after_prerender_ = false;
 }
 
 void PrerenderHistograms::RecordPrerenderStarted(Origin origin) const {
   if (OriginIsOmnibox(origin)) {
-    UMA_HISTOGRAM_COUNTS(
+    UMA_HISTOGRAM_ENUMERATION(

[dominich, 2012/07/23 19:39:47]

I would prefer any of these:

- calling UMA_HISTOGRAM_CUSTOM_COUNTS
- histograms being dynamically sized based on samples
- introducing UMA_HISTOGRAM_SMALL_COUNTS

but given those options, ENUMERATION is fine I guess.

         StringPrintf("Prerender.OmniboxPrerenderCount%s",
-                     PrerenderManager::GetModeString()).c_str(),
-        1);
+                     PrerenderManager::GetModeString()), 1, 2);
   }
 }
 
 void PrerenderHistograms::RecordUsedPrerender(Origin origin) const {
   if (OriginIsOmnibox(origin)) {
-    UMA_HISTOGRAM_COUNTS(
+    UMA_HISTOGRAM_ENUMERATION(
         StringPrintf("Prerender.OmniboxNavigationsUsedPrerenderCount%s",
-                     PrerenderManager::GetModeString()).c_str(),
-        1);
+                     PrerenderManager::GetModeString()), 1, 2);
   }
 }
 
 void PrerenderHistograms::RecordTimeSinceLastRecentVisit(
     base::TimeDelta delta) const {
   PREFIXED_HISTOGRAM(
       "TimeSinceLastRecentVisit",
       UMA_HISTOGRAM_TIMES(name, delta));
 }
 
@@ skipping 228 matching lines @@
       "LocalPredictorTimeUntilUsed",
       UMA_HISTOGRAM_CUSTOM_TIMES(
           name,
           time_until_used,
           base::TimeDelta::FromMilliseconds(10),
           max_age,
           50));
 }
 
 }  // namespace prerender