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

net/disk_cache/rankings.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/rankings.h"
 
 #include "base/histogram.h"
 #include "net/disk_cache/backend_impl.h"
 #include "net/disk_cache/entry_impl.h"
 #include "net/disk_cache/errors.h"
@@ skipping 216 matching lines @@
     // point (we may be in the middle of a cleanup already). Just get rid of
     // the invalid pointer and continue; the entry will be deleted when detected
     // from a regular open/create path.
     rankings->Data()->pointer = NULL;
     return true;
   }
 
   EntryImpl* cache_entry =
       reinterpret_cast<EntryImpl*>(rankings->Data()->pointer);
   rankings->SetData(cache_entry->rankings()->Data());
-  UMA_HISTOGRAM_TIMES(L"DiskCache.GetRankings", Time::Now() - start);
+  UMA_HISTOGRAM_TIMES("DiskCache.GetRankings", Time::Now() - start);
   return true;
 }
 
 void Rankings::Insert(CacheRankingsBlock* node, bool modified, List list) {
   Trace("Insert 0x%x", node->address().value());
   DCHECK(node->HasData());
   Addr& my_head = heads_[list];
   Addr& my_tail = tails_[list];
   Transaction lock(control_data_, node->address(), INSERT, list);
   CacheRankingsBlock head(backend_->File(my_head), my_head);
@@ skipping 134 matching lines @@
 }
 
 // A crash in between Remove and Insert will lead to a dirty entry not on the
 // list. We want to avoid that case as much as we can (as while waiting for IO),
 // but the net effect is just an assert on debug when attempting to remove the
 // entry. Otherwise we'll need reentrant transactions, which is an overkill.
 void Rankings::UpdateRank(CacheRankingsBlock* node, bool modified, List list) {
   Time start = Time::Now();
   Remove(node, list);
   Insert(node, modified, list);
-  UMA_HISTOGRAM_TIMES(L"DiskCache.UpdateRank", Time::Now() - start);
+  UMA_HISTOGRAM_TIMES("DiskCache.UpdateRank", Time::Now() - start);
 }
 
 void Rankings::CompleteTransaction() {
   Addr node_addr(static_cast<CacheAddr>(control_data_->transaction));
   if (!node_addr.is_initialized() || node_addr.is_separate_file()) {
     NOTREACHED();
     LOG(ERROR) << "Invalid rankings info.";
     return;
   }
 
@@ skipping 338 matching lines @@
        ++it) {
     if (it->first == address) {
       CacheRankingsBlock* other = it->second;
       other->Data()->next = node->Data()->next;
       other->Data()->prev = node->Data()->prev;
     }
   }
 }
 
 }  // namespace disk_cache