Add histogram to track number of .nexe launches, normalized against opening new tabs.

BUG=914 (http://code.google.com/p/nativeclient/issues/detail?id=914)
TEST=none
  Relied on trybots and manually checking "about:histograms"

Review URL: http://codereview.chromium.org/4065005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@64261 0039d316-1c4b-4281-b951-d872f2087c98

base/base.gypi

@@ -148,6 +148,8 @@
           'message_pump_win.h',
           'metrics/histogram.cc',
           'metrics/histogram.h',
+          'metrics/nacl_histogram.cc',
+          'metrics/nacl_histogram.h',		  
           'metrics/stats_counters.cc',
           'metrics/stats_counters.h',
           'metrics/stats_table.cc',

base/metrics/nacl_histogram.cc

+// Copyright (c) 2010 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.
+
+// nacl_histogram provides an enum and defines a macro that uses definitions
+// from histogram.h. Note that a histogram is an object that aggregates
+// statistics, and can summarize them in various forms, including ASCII
+// graphical, HTML, and numerically.
+// nacl_histogram information is used to compare how many times a native
+// client module has been loaded, compared to the number of chrome starts
+// and number of new tabs created.
+
+
+#include "base/metrics/histogram.h"
+#include "base/metrics/nacl_histogram.h"
+
+// To log histogram data about NaCl.Startups, call this function with
+// a NaClHistogramValue passed in as |hvalue|
+void UmaNaclHistogramEnumeration(NaClHistogramValue histogram_value) {
+  UMA_HISTOGRAM_ENUMERATION("NaCl.Startups", histogram_value,
+    NACL_MAX_HISTOGRAM);
+}
+

base/metrics/nacl_histogram.h

+// Copyright (c) 2010 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.
+
+// nacl_histogram provides an enum and defines a macro that uses definitions
+// from histogram.h. Note that a histogram is an object that aggregates
+// statistics, and can summarize them in various forms, including ASCII
+// graphical, HTML, and numerically.
+// nacl_histogram information is used to compare how many times a native
+// client module has been loaded, compared to the number of chrome starts
+// and number of new tabs created.
+
+#ifndef BASE_METRICS_NACL_HISTOGRAM_H_
+#define BASE_METRICS_NACL_HISTOGRAM_H_
+#pragma once
+
+enum NaClHistogramValue {
+  FIRST_TAB_NACL_BASELINE,   // First tab created - a baseline for NaCl starts.
+  NEW_TAB_NACL_BASELINE,     // New tab created -- a baseline for NaCl starts.
+  NACL_STARTED,              // NaCl process started
+  NACL_MAX_HISTOGRAM         // DO NOT USE -- used by histogram for max bound.
+};
+
+// To log histogram data about NaCl.Startups, call this macro with
+// a NaClHistogramValue passed in as |histogram_value|
+void UmaNaclHistogramEnumeration(NaClHistogramValue histogram_value);
+
+#endif  // BASE_METRICS_NACL_HISTOGRAM_H_
+

chrome/browser/nacl_host/nacl_process_host.cc

@@ -11,6 +11,7 @@
 #endif
 
 #include "base/command_line.h"
+#include "base/metrics/nacl_histogram.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/renderer_host/resource_message_filter.h"
 #include "chrome/common/chrome_switches.h"
@@ -114,7 +115,7 @@ bool NaClProcessHost::Launch(ResourceMessageFilter* resource_message_filter,
   if (!LaunchSelLdr()) {
     return false;
   }
-
+  UmaNaclHistogramEnumeration(NACL_STARTED);
   resource_message_filter_ = resource_message_filter;
   reply_msg_ = reply_msg;
 

chrome/browser/tabs/default_tab_handler.cc

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/metrics/nacl_histogram.h"
 #include "chrome/browser/tabs/default_tab_handler.h"
-
 #include "chrome/browser/browser.h"
 #include "chrome/browser/tabs/tab_strip_model.h"
 
@@ -14,6 +14,7 @@ DefaultTabHandler::DefaultTabHandler(TabHandlerDelegate* delegate)
     : delegate_(delegate),
       ALLOW_THIS_IN_INITIALIZER_LIST(
         model_(new TabStripModel(this, delegate->GetProfile()))) {
+  UmaNaclHistogramEnumeration(FIRST_TAB_NACL_BASELINE);
   model_->AddObserver(this);
 }
 
@@ -34,6 +35,7 @@ TabStripModel* DefaultTabHandler::GetTabStripModel() const {
 // DefaultTabHandler, TabStripModelDelegate implementation:
 
 TabContents* DefaultTabHandler::AddBlankTab(bool foreground) {
+  UmaNaclHistogramEnumeration(NEW_TAB_NACL_BASELINE);
   return delegate_->AsBrowser()->AddBlankTab(foreground);
 }