NTP: Clean up of MetricsHandler class and namespacing chrome.send messages.

chrome/browser/ui/webui/ntp/metrics_handler.cc

+// Copyright (c) 2011 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.
+
+#include "chrome/browser/ui/webui/ntp/metrics_handler.h"
+
+#include "base/logging.h"
+#include "base/metrics/histogram.h"
+#include "base/utf_string_conversions.h"
+#include "base/values.h"
+#include "chrome/browser/metrics/metric_event_duration_details.h"
+#include "chrome/browser/ui/webui/chrome_web_ui.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "content/browser/tab_contents/tab_contents.h"
+#include "content/browser/user_metrics.h"
+#include "content/common/notification_service.h"
+
+using base::ListValue;
+
+MetricsHandler::MetricsHandler() {}
+MetricsHandler::~MetricsHandler() {}
+
+void MetricsHandler::RegisterMessages() {
+  web_ui_->RegisterMessageCallback("metricsHandler:recordAction",
+      NewCallback(this, &MetricsHandler::HandleRecordAction));
+  web_ui_->RegisterMessageCallback("metricsHandler:recordInHistogram",
+      NewCallback(this, &MetricsHandler::HandleRecordInHistogram));
+  web_ui_->RegisterMessageCallback("metricsHandler:logEventTime",
+      NewCallback(this, &MetricsHandler::HandleLogEventTime));
+}
+
+void MetricsHandler::HandleRecordAction(const ListValue* args) {
+  std::string string_action = UTF16ToUTF8(ExtractStringValue(args));
+  UserMetrics::RecordComputedAction(string_action);
+}
+
+void MetricsHandler::HandleRecordInHistogram(const ListValue* args) {
+  std::string histogram_name;
+  double value;
+  double boundary_value;
+  if (!args->GetString(0, &histogram_name) ||
+      !args->GetDouble(1, &value) ||
+      !args->GetDouble(2, &boundary_value)) {
+    NOTREACHED();
+    return;
+  }
+
+  int int_value = static_cast<int>(value);
+  int int_boundary_value = static_cast<int>(boundary_value);
+  if (int_boundary_value >= 4000 ||
+      int_value > int_boundary_value ||
+      int_value < 0) {
+    NOTREACHED();
+    return;
+  }
+
+  int bucket_count = int_boundary_value;
+  while (bucket_count >= 100) {
+    bucket_count /= 10;
+  }
+
+  // As |histogram_name| may change between calls, the UMA_HISTOGRAM_ENUMERATION
+  // macro cannot be used here.
+  base::Histogram* counter =
+      base::LinearHistogram::FactoryGet(
+          histogram_name, 1, int_boundary_value, bucket_count + 1,
+          base::Histogram::kUmaTargetedHistogramFlag);
+  counter->Add(int_value);
+}
+
+void MetricsHandler::HandleLogEventTime(const ListValue* args) {
+  std::string event_name = UTF16ToUTF8(ExtractStringValue(args));
+  TabContents* tab = web_ui_->tab_contents();
+
+  // Not all new tab pages get timed.  In those cases, we don't have a

[Evan Stade, 2011/10/03 21:34:22]

# of spaces after .

[Dan Beam, 2011/10/03 22:27:03]

Done. (sins of the code's forefather[s])

+  // new_tab_start_time_.
+  if (tab->new_tab_start_time().is_null())
+    return;
+
+  base::TimeDelta duration = base::TimeTicks::Now() - tab->new_tab_start_time();
+  MetricEventDurationDetails details(event_name,
+      static_cast<int>(duration.InMilliseconds()));
+
+  if (event_name == "Tab.NewTabScriptStart") {
+    UMA_HISTOGRAM_TIMES("Tab.NewTabScriptStart", duration);
+  } else if (event_name == "Tab.NewTabDOMContentLoaded") {
+    UMA_HISTOGRAM_TIMES("Tab.NewTabDOMContentLoaded", duration);
+  } else if (event_name == "Tab.NewTabOnload") {
+    UMA_HISTOGRAM_TIMES("Tab.NewTabOnload", duration);
+    // The new tab page has finished loading; reset it.
+    tab->set_new_tab_start_time(base::TimeTicks());
+  } else {
+    NOTREACHED();
+  }
+  NotificationService::current()->Notify(
+      chrome::NOTIFICATION_METRIC_EVENT_DURATION,
+      Source<TabContents>(tab),
+      Details<MetricEventDurationDetails>(&details));
+}