Adds UMA metrics for renderer uptime

chrome/browser/metrics/renderer_uptime_tracker.cc

Index: chrome/browser/metrics/renderer_uptime_tracker.cc
diff --git a/chrome/browser/metrics/renderer_uptime_tracker.cc b/chrome/browser/metrics/renderer_uptime_tracker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..92dba501f493325d2a428c0b3d9b5fbc50f63c54
--- /dev/null
+++ b/chrome/browser/metrics/renderer_uptime_tracker.cc
@@ -0,0 +1,106 @@
+// Copyright 2017 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/metrics/renderer_uptime_tracker.h"
+
+#include "base/metrics/histogram_macros.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
+#include "content/public/browser/render_process_host.h"
+#include "extensions/features/features.h"
+
+#if BUILDFLAG(ENABLE_EXTENSIONS)
+#include "extensions/browser/process_map.h"
+#endif
+
+namespace {
+
+RendererUptimeTracker* g_instance = nullptr;
+
+}  // namespace
+
+// static
+void RendererUptimeTracker::Initialize() {
+  DCHECK(!g_instance);
+  g_instance = new RendererUptimeTracker;
+}
+
+// static
+bool RendererUptimeTracker::IsInitialized() {
+  return g_instance != nullptr;
+}
+
+// static
+RendererUptimeTracker* RendererUptimeTracker::Get() {
+  DCHECK(g_instance);
+  return g_instance;
+}
+
+RendererUptimeTracker::RendererUptimeTracker() {
+  registrar_.Add(this, content::NOTIFICATION_RENDERER_PROCESS_CREATED,
+                 content::NotificationService::AllBrowserContextsAndSources());
+}
+
+RendererUptimeTracker::~RendererUptimeTracker() {}
+
+void RendererUptimeTracker::OnRendererStarted(int pid) {
+  info_map_[pid] = RendererInfo{base::TimeTicks::Now(), 0, 0};
+}
+
+void RendererUptimeTracker::OnRendererTerminated(int pid) {
+  auto it = info_map_.find(pid);
+  if (it != info_map_.end()) {
+    auto uptime = base::TimeTicks::Now() - it->second.launched_at_;
+    UMA_HISTOGRAM_CUSTOM_TIMES("Memory.Experimental.Renderer.Uptime", uptime,
+                               base::TimeDelta::FromHours(1),
+                               base::TimeDelta::FromDays(7), 50);
+    UMA_HISTOGRAM_COUNTS_10000(
+        "Memory.Experimental.Renderer.LoadsInMainFrameDuringUptime",
+        it->second.num_loads_in_main_frame_);
+    info_map_.erase(it);
+  }
+}
+
+void RendererUptimeTracker::OnLoadInMainFrame(int pid) {
+  auto it = info_map_.find(pid);
+  DCHECK(it != info_map_.end());
+  it->second.num_loads_in_main_frame_++;
+}
+
+void RendererUptimeTracker::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  switch (type) {
+    case content::NOTIFICATION_RENDERER_PROCESS_CREATED: {
+      content::RenderProcessHost* host =
+          content::Source<content::RenderProcessHost>(source).ptr();
+#if BUILDFLAG(ENABLE_EXTENSIONS)
+      if (extensions::ProcessMap::Get(host->GetBrowserContext())
+              ->Contains(host->GetID())) {
+        break;
+      }
+#endif
+      OnRendererStarted(host->GetID());
+      break;
+    }
+
+    case content::NOTIFICATION_RENDERER_PROCESS_TERMINATED: {

[Alexei Svitkine (slow), 2017/03/01 15:50:18]

Are you forgetting to a register for this?

[keishi, 2017/03/02 09:37:14]

Done.

+      content::RenderProcessHost* host =
+          content::Source<content::RenderProcessHost>(source).ptr();
+#if BUILDFLAG(ENABLE_EXTENSIONS)
+      if (extensions::ProcessMap::Get(host->GetBrowserContext())
+              ->Contains(host->GetID())) {
+        break;
+      }
+#endif
+      OnRendererTerminated(host->GetID());
+      break;
+    }
+
+    default:
+      NOTREACHED();
+      break;
+  }
+}