Move implementation of BrowserList onto an inner, instantiatable class, BrowserListImpl.

chrome/browser/ui/uma_browsing_activity_observer.cc

+// Copyright (c) 2012 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/uma_browsing_activity_observer.h"
+
+#include "base/metrics/histogram.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/browser_window.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "content/public/browser/navigation_details.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/render_process_host.h"
+
+namespace chrome {
+namespace {
+
+UMABrowsingActivityObserver* g_instance = NULL;
+
+}  // namespace
+
+// static
+void UMABrowsingActivityObserver::Init() {
+  DCHECK(!g_instance);
+  DCHECK(BrowserList::empty());  // Must be created before any Browsers are.
+  g_instance = new UMABrowsingActivityObserver;
+}
+
+UMABrowsingActivityObserver::UMABrowsingActivityObserver() {
+  registrar_.Add(this, content::NOTIFICATION_NAV_ENTRY_COMMITTED,
+                  content::NotificationService::AllSources());
+  registrar_.Add(this, content::NOTIFICATION_APP_TERMINATING,
+                  content::NotificationService::AllSources());
+}
+
+UMABrowsingActivityObserver::~UMABrowsingActivityObserver() {
+}
+
+void UMABrowsingActivityObserver::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  if (type == content::NOTIFICATION_NAV_ENTRY_COMMITTED) {
+    const content::LoadCommittedDetails& load =
+        *content::Details<content::LoadCommittedDetails>(details).ptr();
+    if (!load.is_navigation_to_different_page())
+      return;  // Don't log for subframes or other trivial types.
+
+    LogRenderProcessHostCount();
+    LogBrowserTabCount();
+  } else if (type == content::NOTIFICATION_APP_TERMINATING) {
+    delete g_instance;
+    g_instance = NULL;
+  }
+}
+
+void UMABrowsingActivityObserver::LogRenderProcessHostCount() const {
+  int hosts_count = 0;
+  for (content::RenderProcessHost::iterator i(
+          content::RenderProcessHost::AllHostsIterator());
+        !i.IsAtEnd(); i.Advance())
+    ++hosts_count;
+  UMA_HISTOGRAM_CUSTOM_COUNTS("MPArch.RPHCountPerLoad", hosts_count,
+                              1, 50, 50);
+}
+
+void UMABrowsingActivityObserver::LogBrowserTabCount() const {
+  int tab_count = 0;
+  for (BrowserList::const_iterator browser_iterator = BrowserList::begin();
+        browser_iterator != BrowserList::end(); browser_iterator++) {
+    // Record how many tabs each window has open.
+    Browser* browser = (*browser_iterator);
+    UMA_HISTOGRAM_CUSTOM_COUNTS("Tabs.TabCountPerWindow",
+                                browser->tab_count(), 1, 200, 50);
+    tab_count += browser->tab_count();
+
+    if (browser->window()->IsActive()) {
+      // Record how many tabs the active window has open.
+      UMA_HISTOGRAM_CUSTOM_COUNTS("Tabs.TabCountActiveWindow",
+                                  browser->tab_count(), 1, 200, 50);
+    }
+  }
+  // Record how many tabs total are open (across all windows).
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Tabs.TabCountPerLoad", tab_count, 1, 200, 50);
+}
+
+}  // namespace chrome