Allow histograms in cache stats.cc to bypass corruption checks

This is a relanding of http://codereview.chromium.org/4174002

The change in this CL is that I've made the function
to look for errors virtual, and over-rode it in StatsHistograms.
The current override doesn't actually check for inconsistencies,
so that the UMA checks (and renderer-to-histogram checks) won't
complain and refuse to transport the histograms.

BUG=61281
r=rvargas
Review URL: http://codereview.chromium.org/4364001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@64990 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 7 insertions, 0 deletions

diff --git a/net/disk_cache/stats_histogram.cc b/net/disk_cache/stats_histogram.cc
index bc3f5d3..366a7e1 100644
--- a/net/disk_cache/stats_histogram.cc
+++ b/net/disk_cache/stats_histogram.cc
@@ -86,4 +86,10 @@ void StatsHistogram::SnapshotSample(SampleSet* sample) const {
   mutable_me->ClearFlags(kUmaTargetedHistogramFlag);
 }
 
+Histogram::Inconsistencies StatsHistogram::FindCorruption(
+    const SampleSet& snapshot) const {
+  return NO_INCONSISTENCIES;  // This class won't monitor inconsistencies.
+}
+
+
 }  // namespace disk_cache
diff --git a/net/disk_cache/stats_histogram.h b/net/disk_cache/stats_histogram.h
index cbd8f03..499784c 100644
--- a/net/disk_cache/stats_histogram.h
+++ b/net/disk_cache/stats_histogram.h
@@ -44,6 +44,7 @@ class StatsHistogram : public base::Histogram {
   virtual Sample ranges(size_t i) const;
   virtual size_t bucket_count() const;
   virtual void SnapshotSample(SampleSet* sample) const;
+  virtual Inconsistencies FindCorruption(const SampleSet& snapshot) const;
 
  private:
   bool init_;