Fix a bunch of tiny near-bugs and bugs that static analysis identified...

base/histogram.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.
 
 // Histogram is an object that aggregates statistics, and can summarize them in
 // various forms, including ASCII graphical, HTML, and numerically (as a
 // vector of numbers corresponding to each of the aggregating buckets).
 // See header file for details and examples.
 
 #include "base/histogram.h"
@@ skipping 622 matching lines @@
   StatsRate::Add(-value);
   size_t index = BucketIndex(value);
   Accumulate(value, -1, index);
 }
 
 void ThreadSafeHistogram::Accumulate(Sample value, Count count, size_t index) {
   AutoLock lock(lock_);
   Histogram::Accumulate(value, count, index);
 }
 
-void ThreadSafeHistogram::SnapshotSample(SampleSet* sample) {
+void ThreadSafeHistogram::SnapshotSample(SampleSet* sample) const {
   AutoLock lock(lock_);
   Histogram::SnapshotSample(sample);
 };
 
 
 //------------------------------------------------------------------------------
 // The next section handles global (central) support for all histograms, as well
 // as startup/teardown of this service.
 //------------------------------------------------------------------------------
 
@@ skipping 136 matching lines @@
       snapshot->push_back(it->second);
   }
 }
 
 // static
 StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL;
 // static
 Lock* StatisticsRecorder::lock_ = NULL;
 // static
 bool StatisticsRecorder::dump_on_exit_ = false;