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

2 files changed, 23 insertions, 47 deletions

diff --git a/net/ftp/ftp_network_transaction.cc b/net/ftp/ftp_network_transaction.cc
index 44f1aa1..ec87b8c 100644
--- a/net/ftp/ftp_network_transaction.cc
+++ b/net/ftp/ftp_network_transaction.cc
@@ -1146,18 +1146,14 @@ int FtpNetworkTransaction::DoDataReadComplete(int result) {
   return result;
 }
 
-// We're using a histogram as a group of counters.  We're only interested in
-// the values of the counters.  Ignore the shape, average, and standard
-// deviation of the histograms because they are meaningless.
+// We're using a histogram as a group of counters, with one bucket for each
+// enumeration value.  We're only interested in the values of the counters.
+// Ignore the shape, average, and standard deviation of the histograms because
+// they are meaningless.
 //
-// We use two groups of counters.  In the first group (counter1), each counter
-// is a boolean (0 or 1) that indicates whether the user has seen an error
-// of that type during that session.  In the second group (counter2), each
-// counter is the number of errors of that type the user has seen during
-// that session.
-//
-// Each histogram has an unused bucket at the end to allow seamless future
-// expansion.
+// We use two histograms.  In the first histogram we tally whether the user has
+// seen an error of that type during the session.  In the second histogram we
+// tally the total number of times the users sees each errer.
 void FtpNetworkTransaction::RecordDataConnectionError(int result) {
   // Gather data for http://crbug.com/3073. See how many users have trouble
   // establishing FTP data connection in passive FTP mode.
@@ -1205,23 +1201,15 @@ void FtpNetworkTransaction::RecordDataConnectionError(int result) {
       break;
   };
   static bool had_error_type[NUM_OF_NET_ERROR_TYPES];
-  static scoped_refptr<Histogram> error_flagged =
-      LinearHistogram::LinearHistogramFactoryGet(
-          "Net.FtpDataConnectionErrorHappened",
-          1, NUM_OF_NET_ERROR_TYPES, NUM_OF_NET_ERROR_TYPES + 1);
-  static scoped_refptr<Histogram> error_counter =
-      LinearHistogram::LinearHistogramFactoryGet(
-          "Net.FtpDataConnectionErrorCount",
-          1, NUM_OF_NET_ERROR_TYPES, NUM_OF_NET_ERROR_TYPES + 1);
 
   DCHECK(type >= 0 && type < NUM_OF_NET_ERROR_TYPES);
   if (!had_error_type[type]) {
     had_error_type[type] = true;
-    error_flagged->SetFlags(kUmaTargetedHistogramFlag);
-    error_flagged->Add(type);
+    UMA_HISTOGRAM_ENUMERATION("Net.FtpDataConnectionErrorHappened",
+        type, NUM_OF_NET_ERROR_TYPES);
   }
-  error_counter->SetFlags(kUmaTargetedHistogramFlag);
-  error_counter->Add(type);
+  UMA_HISTOGRAM_ENUMERATION("Net.FtpDataConnectionErrorCount",
+      type, NUM_OF_NET_ERROR_TYPES);
 }
 
 }  // namespace net
diff --git a/net/ftp/ftp_server_type_histograms.cc b/net/ftp/ftp_server_type_histograms.cc
index 60ab9b9..de90d72 100644
--- a/net/ftp/ftp_server_type_histograms.cc
+++ b/net/ftp/ftp_server_type_histograms.cc
@@ -8,38 +8,26 @@
 
 namespace net {
 
-// We're using a histogram as a group of counters.  We're only interested in
-// the values of the counters.  Ignore the shape, average, and standard
-// deviation of the histograms because they are meaningless.
+// We're using a histogram as a group of counters, with one bucket for each
+// enumeration value.  We're only interested in the values of the counters.
+// Ignore the shape, average, and standard deviation of the histograms because
+// they are meaningless.
 //
-// We use two groups of counters.  In the first group (counter1), each counter
-// is a boolean (0 or 1) that indicates whether the user has seen an FTP server
-// of that type during that session.  In the second group (counter2), each
-// counter is the number of transactions with FTP server of that type the user
-// has made during that session.
-//
-// Each histogram has an unused bucket at the end to allow seamless future
-// expansion.
+// We use two histograms.  In the first histogram we tally whether the user has
+// seen an FTP server of a given type during that session.  In the second
+// histogram we tally the number of transactions with FTP server of a given type
+// the user has made during that session.
 void UpdateFtpServerTypeHistograms(FtpServerType type) {
   static bool had_server_type[NUM_OF_SERVER_TYPES];
-  static scoped_refptr<Histogram> counter1 =
-      LinearHistogram::LinearHistogramFactoryGet("Net.HadFtpServerType",
-                                                 1, NUM_OF_SERVER_TYPES,
-                                                 NUM_OF_SERVER_TYPES + 1);
-  static scoped_refptr<Histogram> counter2 =
-      LinearHistogram::LinearHistogramFactoryGet("Net.FtpServerTypeCount",
-                                                 1, NUM_OF_SERVER_TYPES,
-                                                 NUM_OF_SERVER_TYPES + 1);
-
   if (type >= 0 && type < NUM_OF_SERVER_TYPES) {
     if (!had_server_type[type]) {
       had_server_type[type] = true;
-      counter1->SetFlags(kUmaTargetedHistogramFlag);
-      counter1->Add(type);
+      UMA_HISTOGRAM_ENUMERATION("Net.HadFtpServerType",
+                                type, NUM_OF_SERVER_TYPES);
     }
   }
-  counter2->SetFlags(kUmaTargetedHistogramFlag);
-  counter2->Add(type);
+  UMA_HISTOGRAM_ENUMERATION("Net.FtpServerTypeCount",
+                            type, NUM_OF_SERVER_TYPES);
 }
 
 }  // namespace net