Implement the content/renderer and content/browser part of the Device Motion API.

content/browser/device_orientation/device_motion_service.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/browser/device_orientation/device_motion_service.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/memory/singleton.h"
+#include "content/browser/device_orientation/device_motion_provider.h"
+#include "content/public/browser/render_process_host.h"
+
+namespace content {
+
+DeviceMotionService::DeviceMotionService()
+    : num_readers_(0),
+      is_shutdown_(false) {
+}
+
+DeviceMotionService::~DeviceMotionService() {
+}
+
+DeviceMotionService* DeviceMotionService::GetInstance() {
+  return Singleton<DeviceMotionService,
+                   LeakySingletonTraits<DeviceMotionService> >::get();
+}
+
+void DeviceMotionService::AddConsumer() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (is_shutdown_)
+    return;
+
+  num_readers_++;
+  DCHECK(num_readers_ > 0);
+  if (!provider_.get())
+    provider_.reset(new DeviceMotionProvider);
+  provider_->StartFetchingDeviceMotionData();
+}
+
+void DeviceMotionService::RemoveConsumer() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (is_shutdown_)
+    return;
+
+  --num_readers_;
+  DCHECK(num_readers_ >= 0);
+
+  if (num_readers_ == 0) {
+    LOG(INFO) << "ACTIVE service stop fetching";
+    provider_->StopFetchingDeviceMotionData();
+  }
+}
+
+void DeviceMotionService::Shutdown() {
+  provider_.reset();
+  is_shutdown_ = true;
+}
+
+base::SharedMemoryHandle DeviceMotionService::GetSharedMemoryHandleForProcess(
+    base::ProcessHandle handle) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return provider_->GetSharedMemoryHandleForProcess(handle);
+}
+
+}  // namespace content