Cleanup histogram classes mixing SetFlags into FactoryGet arguments

Generic cleanup of histogram class, renaming *FactoryGet to FactoryGet,
along with reformatting.

The macros were cleaned up to use common sub-macros rather than
repeating code as much.

Removed ThreadSafeHistogram (and associated ASSET_HISTOGRAM macros)
since this class was not getting used.

I introduced UMA_HISTOGRAM_ENUMERATION to support the common use
of LinearHistograms to count various enumerated values.

I added a Flags argument to all the FactoryGet routines to help avoid 
needing to call SetFlags each time a new sample is Add()ed.  This also
simplifies the code.

This will all help prepare for a "don't histogram at all" macro setting
so that I can test the impact of the histogram macro calls on
performance (since there are now so many active histograms).

BUG=31206
r=raman.tenneti
Review URL: http://codereview.chromium.org/515033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@35295 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 2 insertions, 3 deletions

diff --git a/net/base/mime_sniffer.cc b/net/base/mime_sniffer.cc
index df0f171..8e063cb 100644
--- a/net/base/mime_sniffer.cc
+++ b/net/base/mime_sniffer.cc
@@ -213,9 +213,8 @@ static const MagicNumber kSniffableTags[] = {
 static scoped_refptr<Histogram> UMASnifferHistogramGet(const char* name,
                                                        int array_size) {
   scoped_refptr<Histogram> counter =
-      LinearHistogram::LinearHistogramFactoryGet(
-          name, 1, array_size - 1, array_size);
-  counter->SetFlags(kUmaTargetedHistogramFlag);
+      LinearHistogram::FactoryGet(name, 1, array_size - 1, array_size,
+      Histogram::kUmaTargetedHistogramFlag);
   return counter;
 }