arc: Revamp the ArcBridgeService interface

components/arc/metrics/arc_metrics_service.cc

 // Copyright 2016 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 "components/arc/metrics/arc_metrics_service.h"
 
+#include <string>
+
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/session_manager_client.h"
 
 namespace {
 
 const int kRequestProcessListPeriodInMinutes = 5;
 const char kArcProcessNamePrefix[] = "org.chromium.arc.";
 const char kGmsProcessNamePrefix[] = "com.google.android.gms";
 const char kBootProgressEnableScreen[] = "boot_progress_enable_screen";
 
-} // namespace
+}  // namespace
 
 namespace arc {
 
 ArcMetricsService::ArcMetricsService(ArcBridgeService* bridge_service)
-    : ArcService(bridge_service), binding_(this), weak_ptr_factory_(this) {
-  arc_bridge_service()->AddObserver(this);
+    : ArcService(bridge_service),
+      binding_(this),
+      process_observer_(this),
+      weak_ptr_factory_(this) {
+  arc_bridge_service()->metrics()->AddObserver(this);
+  arc_bridge_service()->process()->AddObserver(&process_observer_);
   oom_kills_monitor_.Start();
 }
 
 ArcMetricsService::~ArcMetricsService() {
   DCHECK(CalledOnValidThread());
-  arc_bridge_service()->RemoveObserver(this);
+  arc_bridge_service()->process()->RemoveObserver(&process_observer_);
+  arc_bridge_service()->metrics()->RemoveObserver(this);
 }
 
 bool ArcMetricsService::CalledOnValidThread() {
   // Make sure access to the Chrome clipboard is happening in the UI thread.
   return thread_checker_.CalledOnValidThread();
 }
 
-void ArcMetricsService::OnMetricsInstanceReady() {
+void ArcMetricsService::OnInstanceReady() {
   VLOG(2) << "Start metrics service.";
   // Retrieve ARC start time from session manager.
   chromeos::SessionManagerClient* session_manager_client =
       chromeos::DBusThreadManager::Get()->GetSessionManagerClient();
   session_manager_client->GetArcStartTime(
       base::Bind(&ArcMetricsService::OnArcStartTimeRetrieved,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
-void ArcMetricsService::OnMetricsInstanceClosed() {
+void ArcMetricsService::OnInstanceClosed() {
   VLOG(2) << "Close metrics service.";
   DCHECK(CalledOnValidThread());
   if (binding_.is_bound())
     binding_.Unbind();
 }
 
 void ArcMetricsService::OnProcessInstanceReady() {
   VLOG(2) << "Start updating process list.";
-  timer_.Start(
-      FROM_HERE,
-      base::TimeDelta::FromMinutes(kRequestProcessListPeriodInMinutes),
-      this,
-      &ArcMetricsService::RequestProcessList);
+  timer_.Start(FROM_HERE,
+               base::TimeDelta::FromMinutes(kRequestProcessListPeriodInMinutes),
+               this, &ArcMetricsService::RequestProcessList);
 }
 
 void ArcMetricsService::OnProcessInstanceClosed() {
   VLOG(2) << "Stop updating process list.";
   timer_.Stop();
 }
 
 void ArcMetricsService::RequestProcessList() {
   mojom::ProcessInstance* process_instance =
-      arc_bridge_service()->process_instance();
+      arc_bridge_service()->process()->instance();
   if (!process_instance) {
     LOG(ERROR) << "No process instance found before RequestProcessList";
     return;
   }
 
   VLOG(2) << "RequestProcessList";
-  process_instance->RequestProcessList(
-      base::Bind(&ArcMetricsService::ParseProcessList,
-                 weak_ptr_factory_.GetWeakPtr()));
+  process_instance->RequestProcessList(base::Bind(
+      &ArcMetricsService::ParseProcessList, weak_ptr_factory_.GetWeakPtr()));
 }
 
 void ArcMetricsService::ParseProcessList(
     mojo::Array<arc::mojom::RunningAppProcessInfoPtr> processes) {
   int running_app_count = 0;
   for (const auto& process : processes) {
     const mojo::String& process_name = process->process_name;
     const mojom::ProcessState& process_state = process->process_state;
 
     // Processes like the ARC launcher and intent helper are always running
     // and not counted as apps running by users. With the same reasoning,
     // GMS (Google Play Services) and its related processes are skipped as
     // well. The process_state check below filters out system processes,
     // services, apps that are cached because they've run before.
     if (base::StartsWith(process_name.get(), kArcProcessNamePrefix,
                          base::CompareCase::SENSITIVE) ||
         base::StartsWith(process_name.get(), kGmsProcessNamePrefix,
                          base::CompareCase::SENSITIVE) ||
         process_state != mojom::ProcessState::TOP) {
       VLOG(2) << "Skipped " << process_name << " " << process_state;
     } else {
       ++running_app_count;
     }
   }
 
   UMA_HISTOGRAM_COUNTS_100("Arc.AppCount", running_app_count);
 }
 
 void ArcMetricsService::OnArcStartTimeRetrieved(
-    bool success, base::TimeTicks arc_start_time) {
+    bool success,
+    base::TimeTicks arc_start_time) {
   DCHECK(CalledOnValidThread());
   if (!success) {
     LOG(ERROR) << "Failed to retrieve ARC start timeticks.";
     return;
   }
+  if (!arc_bridge_service()->metrics()->instance()) {
+    LOG(ERROR) << "ARC metrics instance went away while retrieving start time.";
+    return;
+  }
 
   // The binding of host interface is deferred until the ARC start time is
   // retrieved here because it prevents race condition of the ARC start
   // time availability in ReportBootProgress().
   if (!binding_.is_bound()) {
     mojom::MetricsHostPtr host_ptr;
     binding_.Bind(mojo::GetProxy(&host_ptr));
-    arc_bridge_service()->metrics_instance()->Init(std::move(host_ptr));
+    arc_bridge_service()->metrics()->instance()->Init(std::move(host_ptr));
   }
   arc_start_time_ = arc_start_time;
   VLOG(2) << "ARC start @" << arc_start_time_;
 }
 
 void ArcMetricsService::ReportBootProgress(
     mojo::Array<arc::mojom::BootProgressEventPtr> events) {
   DCHECK(CalledOnValidThread());
   int64_t arc_start_time_in_ms =
       (arc_start_time_ - base::TimeTicks()).InMilliseconds();
   for (const auto& event : events) {
-    VLOG(2) << "Report boot progress event:"
-        << event->event << "@" << event->uptimeMillis;
+    VLOG(2) << "Report boot progress event:" << event->event << "@"
+            << event->uptimeMillis;
     std::string title = "Arc." + event->event.get();
     base::TimeDelta elapsed_time = base::TimeDelta::FromMilliseconds(
         event->uptimeMillis - arc_start_time_in_ms);
     // Note: This leaks memory, which is expected behavior.
-    base::HistogramBase* histogram =
-        base::Histogram::FactoryTimeGet(
-            title,
-            base::TimeDelta::FromMilliseconds(1),
-            base::TimeDelta::FromSeconds(30),
-            50,
-            base::HistogramBase::kUmaTargetedHistogramFlag);
+    base::HistogramBase* histogram = base::Histogram::FactoryTimeGet(
+        title, base::TimeDelta::FromMilliseconds(1),
+        base::TimeDelta::FromSeconds(30), 50,
+        base::HistogramBase::kUmaTargetedHistogramFlag);
     histogram->AddTime(elapsed_time);
     if (event->event.get().compare(kBootProgressEnableScreen) == 0)
-      UMA_HISTOGRAM_CUSTOM_TIMES("Arc.AndroidBootTime",
-                                 elapsed_time,
+      UMA_HISTOGRAM_CUSTOM_TIMES("Arc.AndroidBootTime", elapsed_time,
                                  base::TimeDelta::FromMilliseconds(1),
-                                 base::TimeDelta::FromSeconds(30),
-                                 50);
+                                 base::TimeDelta::FromSeconds(30), 50);
   }
 }
 
+ArcMetricsService::ProcessObserver::ProcessObserver(
+    ArcMetricsService* arc_metrics_service)
+    : arc_metrics_service_(arc_metrics_service) {}
+
+ArcMetricsService::ProcessObserver::~ProcessObserver() = default;
+
+void ArcMetricsService::ProcessObserver::OnInstanceReady() {
+  arc_metrics_service_->OnProcessInstanceReady();
+}
+
+void ArcMetricsService::ProcessObserver::OnInstanceClosed() {
+  arc_metrics_service_->OnProcessInstanceClosed();
+}
+
 }  // namespace arc