Implement DeviceMotionEvent API

content/browser/device_sensors/data_fetcher_shared_memory_chromeos.cc

 // Copyright 2015 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_sensors/data_fetcher_shared_memory.h"
 
 #include "content/browser/device_sensors/sensor_manager_chromeos.h"
 
 namespace content {
 
 DataFetcherSharedMemory::DataFetcherSharedMemory() {
 }
 
 DataFetcherSharedMemory::~DataFetcherSharedMemory() {
 }
 
 bool DataFetcherSharedMemory::Start(ConsumerType consumer_type, void* buffer) {
   DCHECK(buffer);
   if (!sensor_manager_)
     sensor_manager_.reset(new SensorManagerChromeOS);
 
   switch (consumer_type) {
     case CONSUMER_TYPE_MOTION:
-      // TODO(jonross): Implement Device Motion API. (crbug.com/427662)
-      NOTIMPLEMENTED();
-      return false;
+      sensor_manager_->StartFetchingDeviceMotionData(
+          static_cast<DeviceMotionHardwareBuffer*>(buffer));
+      return true;

[timvolodine, 2015/03/09 15:55:57]

is there any reason to ignore the return value of StartFetchingDeviceMotionData
and always return true?

[flackr, 2015/03/09 16:21:19]

Oh, I had suggested since the function could not return anything but true to
simply return true and make the function void. Looks like it still returns a
bool though.

[jonross, 2015/03/09 16:35:26]

I'll update the functions to be void

[jonross, 2015/03/09 20:46:24]

Done.

[timvolodine, 2015/03/10 13:03:08]

curious: so there is always an accelerometer available on chromeOS?
i.e. is it possible that there is simply no sensor and what would happen in that
case?

[jonross, 2015/03/10 15:03:58]

It is possible for there to be no sensor on ChromeOS. Currently ChromeOS would
just never fire an OnAccelerometerUpdate event. 

[flackr, 2015/03/10 17:21:11]

If this *should* fail (return false) when there is no accelerometer we should
probably follow up with this. I wonder though if we'll have a race if this is
called at startup before we know if there's an accelerometer.

[timvolodine, 2015/03/10 17:31:32]

Yes so in case there is no sensor the API should actually fire a "null" event
(as per specification). I am fine if this will be addressed in a follow-up
patch.

     case CONSUMER_TYPE_ORIENTATION:
-      return sensor_manager_->StartFetchingDeviceOrientationData(
+      sensor_manager_->StartFetchingDeviceOrientationData(
           static_cast<DeviceOrientationHardwareBuffer*>(buffer));
+      return true;

[timvolodine, 2015/03/09 15:55:57]

same question here

[jonross, 2015/03/09 20:46:24]

Done.

     case CONSUMER_TYPE_LIGHT:
       NOTIMPLEMENTED();
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 bool DataFetcherSharedMemory::Stop(ConsumerType consumer_type) {
   switch (consumer_type) {
     case CONSUMER_TYPE_MOTION:
-      NOTIMPLEMENTED();
-      return false;
+      return sensor_manager_->StopFetchingDeviceMotionData();
     case CONSUMER_TYPE_ORIENTATION:
       return sensor_manager_->StopFetchingDeviceOrientationData();
     case CONSUMER_TYPE_LIGHT:
       NOTIMPLEMENTED();
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace content