chromeos: Add operations to monitor the screen orientation.

content/browser/sensors/sensors_source_chromeos.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 "content/browser/sensors/sensors_source_chromeos.h"
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "chromeos/dbus/service_constants.h"
+#include "content/browser/browser_thread.h"
+#include "content/browser/sensors/sensors_provider.h"
+#include "dbus/bus.h"
+#include "dbus/message.h"
+#include "dbus/object_proxy.h"
+
+namespace sensors {
+
+SensorsSourceChromeos::SensorsSourceChromeos() : sensors_proxy_(NULL) {
+}
+
+bool SensorsSourceChromeos::Init() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(BrowserThread::IsMessageLoopValid(BrowserThread::IO));
+
+  dbus::Bus::Options options;
+  options.bus_type = dbus::Bus::SYSTEM;
+  options.connection_type = dbus::Bus::PRIVATE;
+  options.dbus_thread_message_loop_proxy =
+      BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO);
+  bus_ = new dbus::Bus(options);
+
+  sensors_proxy_ = bus_->GetObjectProxy(chromeos::kSensorsServiceName,
+                                        chromeos::kSensorsServicePath);
+  sensors_proxy_->ConnectToSignal(chromeos::kSensorsServiceInterface,
+                                  chromeos::kScreenOrientationChanged,
+      base::Bind(&SensorsSourceChromeos::OrientationChangedReceived, this),
+      base::Bind(&SensorsSourceChromeos::OrientationChangedConnected, this));
+  return true;

[sky, 2011/09/12 21:21:19]

This always returns true. Is there any point in a return value?

[cwolfe, 2011/09/12 22:15:55]

Only for consistency with other Inits. There was previously a PostTask in here,
but ConnectToSignal doesn't currently report failure.

+}
+
+void SensorsSourceChromeos::Stop() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

[sky, 2011/09/12 21:21:19]

I don't see this getting invoked. When is it invoked?

[cwolfe, 2011/09/12 22:15:55]

Just the destructor at the moment. Initially added it in case I needed a
shutdown hook other than the destructor of ChromeBrowserMainPartsChromeos.

+  if (bus_)
+    bus_->ShutdownOnDBusThreadAndBlock();
+}
+
+SensorsSourceChromeos::~SensorsSourceChromeos() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

[sky, 2011/09/12 21:21:19]

How are you guaranteeing this is going to be deleted on the UI thread?

[cwolfe, 2011/09/12 22:15:55]

Now that I finally re-located DeleteOnUIThread, using it.

+  Stop();
+}
+
+void SensorsSourceChromeos::OrientationChangedReceived(dbus::Signal* signal) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  ScreenOrientation orientation;
+
+  dbus::MessageReader reader(signal);
+  int32 upward = 0;
+  if (!reader.PopInt32(&upward)) {
+    LOG(WARNING) << "Orientation changed signal had incorrect parameters: "
+                 << signal->ToString();
+    return;
+  }
+  orientation.upward = static_cast<ScreenOrientation::Side>(upward);
+
+  Provider::GetInstance()->ScreenOrientationChanged(orientation);
+}
+
+void SensorsSourceChromeos::OrientationChangedConnected(
+    const std::string& interface_name,
+    const std::string& signal_name,
+    bool success) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (!success)
+    LOG(WARNING) << "Failed to connect to orientation changed signal.";
+}
+
+}  // namespace sensors