Simple Cache: report age by (stream -> entry)

net/disk_cache/simple/simple_synchronous_entry.cc

 // Copyright (c) 2013 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/simple/simple_synchronous_entry.h"
 
 #include <algorithm>
 #include <cstring>
 #include <functional>
 #include <limits>
@@ skipping 502 matching lines @@
       return false;
     }
   }
 
   have_open_files_ = true;
   if (create) {
     out_entry_stat->last_modified = out_entry_stat->last_used = Time::Now();
     for (int i = 0; i < kSimpleEntryFileCount; ++i)
       out_entry_stat->data_size[i] = 0;
   } else {
+    base::TimeDelta entry_age = base::Time::Now() - base::Time::UnixEpoch();
     for (int i = 0; i < kSimpleEntryFileCount; ++i) {
       PlatformFileInfo file_info;
       bool success = GetPlatformFileInfo(files_[i], &file_info);
       base::Time file_last_modified;
       if (!success) {
         DLOG(WARNING) << "Could not get platform file info.";
         continue;
       }
       out_entry_stat->last_used = file_info.last_accessed;
       if (simple_util::GetMTime(path_, &file_last_modified))
         out_entry_stat->last_modified = file_last_modified;
       else
         out_entry_stat->last_modified = file_info.last_modified;
 
-      base::TimeDelta entry_age =
+      base::TimeDelta stream_age =
           base::Time::Now() - out_entry_stat->last_modified;
-      SIMPLE_CACHE_UMA(CUSTOM_COUNTS,
-                       "SyncOpenEntryAge", cache_type_,
-                       entry_age.InHours(), 1, 1000, 50);
+      if (stream_age < entry_age)
+        entry_age = stream_age;
 
       // Keep the file size in |data size_| briefly until the key is initialized
       // properly.
       out_entry_stat->data_size[i] = file_info.size;
     }
+    SIMPLE_CACHE_UMA(CUSTOM_COUNTS,
+                     "SyncOpenEntryAge", cache_type_,
+                     entry_age.InHours(), 1, 1000, 50);
   }
 
   return true;
 }
 
 void SimpleSynchronousEntry::CloseFiles() {
   for (int i = 0; i < kSimpleEntryFileCount; ++i) {
     DCHECK_NE(kInvalidPlatformFileValue, files_[i]);
     bool did_close = ClosePlatformFile(files_[i]);
     DCHECK(did_close);
@@ skipping 98 matching lines @@
   initialized_ = true;
   return net::OK;
 }
 
 void SimpleSynchronousEntry::Doom() const {
   // TODO(gavinp): Consider if we should guard against redundant Doom() calls.
   DeleteFilesForEntryHash(path_, entry_hash_);
 }
 
 }  // namespace disk_cache