Disk Cache: Exclude new caches from FilesAge histogram.

net/disk_cache/backend_impl.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 "net/disk_cache/backend_impl.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
@@ skipping 1878 matching lines @@
   CACHE_UMA(COUNTS_10000, "TotalFatalErrors", 0,
             static_cast<int>(stats_.GetCounter(Stats::FATAL_ERROR)));
   CACHE_UMA(COUNTS_10000, "TotalDoomCache", 0,
             static_cast<int>(stats_.GetCounter(Stats::DOOM_CACHE)));
   CACHE_UMA(COUNTS_10000, "TotalDoomRecentEntries", 0,
             static_cast<int>(stats_.GetCounter(Stats::DOOM_RECENT)));
   stats_.SetCounter(Stats::FATAL_ERROR, 0);
   stats_.SetCounter(Stats::DOOM_CACHE, 0);
   stats_.SetCounter(Stats::DOOM_RECENT, 0);
 
-  CACHE_UMA(AGE, "FilesAge", 0,
-            Time::FromInternalValue(data_->header.create_time));
+  int age = (Time::Now() -
+             Time::FromInternalValue(data_->header.create_time)).InHours();
+  if (age)
+    CACHE_UMA(HOURS, "FilesAge", 0, age);
 
   int64 total_hours = stats_.GetCounter(Stats::TIMER) / 120;
   if (!data_->header.create_time || !data_->header.lru.filled) {
     int cause = data_->header.create_time ? 0 : 1;
     if (!data_->header.lru.filled)
       cause |= 2;
     CACHE_UMA(CACHE_ERROR, "ShortReport", 0, cause);
     CACHE_UMA(HOURS, "TotalTimeNotFull", 0, static_cast<int>(total_hours));
     return;
   }
@@ skipping 201 matching lines @@
     if (total_memory > kMaxBuffersSize || total_memory <= 0)
       total_memory = kMaxBuffersSize;
 
     done = true;
   }
 
   return static_cast<int>(total_memory);
 }
 
 }  // namespace disk_cache