Use string for Histogram names since these are all ASCII anyway wide-characte...

net/disk_cache/eviction.cc

 // Copyright (c) 2006-2008 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/eviction.h"
 
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/string_util.h"
 #include "base/time.h"
@@ skipping 62 matching lines @@
       if (++deleted == 4 && !empty) {
 #if defined(OS_WIN)
         MessageLoop::current()->PostTask(FROM_HERE,
             factory_.NewRunnableMethod(&Eviction::TrimCache, false));
         break;
 #endif
       }
     }
   }
 
-  UMA_HISTOGRAM_TIMES(L"DiskCache.TotalTrimTime", Time::Now() - start);
+  UMA_HISTOGRAM_TIMES("DiskCache.TotalTrimTime", Time::Now() - start);
   Trace("*** Trim Cache end ***");
   return;
 }
 
 void Eviction::UpdateRank(EntryImpl* entry, bool modified) {
   rankings_->UpdateRank(entry->rankings(), modified, GetListForEntry(entry));
 }
 
 void Eviction::OnOpenEntry(EntryImpl* entry) {
 }
 
 void Eviction::OnCreateEntry(EntryImpl* entry) {
   rankings_->Insert(entry->rankings(), true, GetListForEntry(entry));
 }
 
 void Eviction::OnDoomEntry(EntryImpl* entry) {
   rankings_->Remove(entry->rankings(), GetListForEntry(entry));
 }
 
 void Eviction::OnDestroyEntry(EntryImpl* entry) {
 }
 
 void Eviction::ReportTrimTimes(EntryImpl* entry) {
   static bool first_time = true;
   if (first_time) {
     first_time = false;
-    std::wstring name(StringPrintf(L"DiskCache.TrimAge_%d",
-                                   header_->experiment));
+    std::string name(StringPrintf("DiskCache.TrimAge_%d",
+                                  header_->experiment));
     static Histogram counter(name.c_str(), 1, 10000, 50);
     counter.SetFlags(kUmaTargetedHistogramFlag);
     counter.Add((Time::Now() - entry->GetLastUsed()).InHours());
   }
 }
 
 Rankings::List Eviction::GetListForEntry(EntryImpl* entry) {
   return Rankings::NO_USE;
 }
 
 }  // namespace disk_cache