Mojoify PoweMonitorMessageBroadcaster IPC from browser to child process

content/child/power_monitor_broadcast_source.cc

 // Copyright (c) 2013 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 "content/child/power_monitor_broadcast_source.h"
 
 #include "base/location.h"
 #include "base/macros.h"
-#include "base/single_thread_task_runner.h"
-#include "base/threading/thread_task_runner_handle.h"
-#include "content/common/power_monitor_messages.h"
-#include "ipc/message_filter.h"
+#include "content/child/child_thread_impl.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "services/service_manager/public/cpp/interface_provider.h"
 
 namespace content {
 
-class PowerMessageFilter : public IPC::MessageFilter {
- public:
-  PowerMessageFilter(PowerMonitorBroadcastSource* source,
-                     scoped_refptr<base::SingleThreadTaskRunner> task_runner)
-      : source_(source), task_runner_(task_runner) {}
-
-  bool OnMessageReceived(const IPC::Message& message) override {
-    bool handled = true;
-    IPC_BEGIN_MESSAGE_MAP(PowerMessageFilter, message)
-      IPC_MESSAGE_HANDLER(PowerMonitorMsg_PowerStateChange, OnPowerStateChange)
-      IPC_MESSAGE_HANDLER(PowerMonitorMsg_Suspend, OnSuspend)
-      IPC_MESSAGE_HANDLER(PowerMonitorMsg_Resume, OnResume)
-      IPC_MESSAGE_UNHANDLED(handled = false)
-    IPC_END_MESSAGE_MAP()
-    return handled;
+PowerMonitorBroadcastSource::PowerMonitorBroadcastSource()
+    : last_reported_battery_power_state_(false), binding_(this) {
+  // May be null during test execution.
+  if (ChildThreadImpl::current()) {
+    device::mojom::PowerMonitorPtr power_monitor;
+    ChildThreadImpl::current()->GetRemoteInterfaces()->GetInterface(
+        mojo::GetProxy(&power_monitor));
+    power_monitor->AddClient(binding_.CreateInterfacePtrAndBind());

[blundell, 2016/10/25 16:53:44]

There's a threading change here I think: Before the IPC would come in on the
child process' IO thread, whereas now it will come in on the thread that
PowerMonitorBroadcastSource lives on (presumably the main thread). rockot@, do
you know if having this communication on the main thread in the child process is
OK as a general rule?

[Ken Rockot(use gerrit already), 2016/10/25 16:56:14]

Yeah this is fine. The new dispatch behavior is effectively the same as before.

   }
-
-  void RemoveSource() {
-    source_ = NULL;
-  }
-
- private:
-  friend class base::RefCounted<PowerMessageFilter>;
-
-  ~PowerMessageFilter() override{};
-
-  void OnPowerStateChange(bool on_battery_power) {
-    task_runner_->PostTask(
-        FROM_HERE, base::Bind(&PowerMessageFilter::NotifySourcePowerStateChange,
-                              this, on_battery_power));
-  }
-  void OnSuspend() {
-    task_runner_->PostTask(
-        FROM_HERE, base::Bind(&PowerMessageFilter::NotifySourceSuspend, this));
-  }
-  void OnResume() {
-    task_runner_->PostTask(
-        FROM_HERE, base::Bind(&PowerMessageFilter::NotifySourceResume, this));
-  }
-
-  void NotifySourcePowerStateChange(bool on_battery_power) {
-    if (source_)
-      source_->OnPowerStateChange(on_battery_power);
-  }
-  void NotifySourceSuspend() {
-    if (source_)
-      source_->OnSuspend();
-  }
-  void NotifySourceResume() {
-     if (source_)
-      source_->OnResume();
-  }
-
-  // source_ should only be accessed on the thread associated with
-  // message_loop_.
-  PowerMonitorBroadcastSource* source_;
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
-
-  DISALLOW_COPY_AND_ASSIGN(PowerMessageFilter);
-};
-
-PowerMonitorBroadcastSource::PowerMonitorBroadcastSource()
-    : last_reported_battery_power_state_(false) {
-  message_filter_ =
-      new PowerMessageFilter(this, base::ThreadTaskRunnerHandle::Get());
 }
 
 PowerMonitorBroadcastSource::~PowerMonitorBroadcastSource() {
-  message_filter_->RemoveSource();
-}
-
-IPC::MessageFilter* PowerMonitorBroadcastSource::GetMessageFilter() {
-  return message_filter_.get();
 }
 
 bool PowerMonitorBroadcastSource::IsOnBatteryPowerImpl() {
   return last_reported_battery_power_state_;
 }
 
-void PowerMonitorBroadcastSource::OnPowerStateChange(bool on_battery_power) {
+void PowerMonitorBroadcastSource::PowerStateChange(bool on_battery_power) {
   last_reported_battery_power_state_ = on_battery_power;
   ProcessPowerEvent(PowerMonitorSource::POWER_STATE_EVENT);
 }
 
-void PowerMonitorBroadcastSource::OnSuspend() {
+void PowerMonitorBroadcastSource::Suspend() {
   ProcessPowerEvent(PowerMonitorSource::SUSPEND_EVENT);
 }
 
-void PowerMonitorBroadcastSource::OnResume() {
+void PowerMonitorBroadcastSource::Resume() {
   ProcessPowerEvent(PowerMonitorSource::RESUME_EVENT);
 }
 
 }  // namespace content