Android: add support for Device Orientation on devices where ROTATION_VECTOR is not availabl…

content/browser/device_sensors/sensor_manager_android.cc

 // Copyright 2014 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/sensor_manager_android.h"
 
 #include <string.h>
 
 #include "base/android/jni_android.h"
 #include "base/memory/singleton.h"
@@ skipping 13 matching lines @@
 
 namespace content {
 
 SensorManagerAndroid::SensorManagerAndroid()
     : number_active_device_motion_sensors_(0),
       device_light_buffer_(NULL),
       device_motion_buffer_(NULL),
       device_orientation_buffer_(NULL),
       is_light_buffer_ready_(false),
       is_motion_buffer_ready_(false),
-      is_orientation_buffer_ready_(false) {
+      is_orientation_buffer_ready_(false),
+      is_using_backup_sensors_for_orientation_(false) {
   memset(received_motion_data_, 0, sizeof(received_motion_data_));
   device_sensors_.Reset(Java_DeviceSensors_getInstance(
       AttachCurrentThread(), base::android::GetApplicationContext()));
 }
 
 SensorManagerAndroid::~SensorManagerAndroid() {
 }
 
 bool SensorManagerAndroid::Register(JNIEnv* env) {
   return RegisterNativesImpl(env);
@@ skipping 15 matching lines @@
   device_orientation_buffer_->data.alpha = alpha;
   device_orientation_buffer_->data.hasAlpha = true;
   device_orientation_buffer_->data.beta = beta;
   device_orientation_buffer_->data.hasBeta = true;
   device_orientation_buffer_->data.gamma = gamma;
   device_orientation_buffer_->data.hasGamma = true;
   device_orientation_buffer_->seqlock.WriteEnd();
 
   if (!is_orientation_buffer_ready_) {
     SetOrientationBufferReadyStatus(true);
-    updateRotationVectorHistogram(true);
+    updateRotationVectorHistogram(!is_using_backup_sensors_for_orientation_);
   }
 }
 
 void SensorManagerAndroid::GotAcceleration(
     JNIEnv*, jobject, double x, double y, double z) {
   base::AutoLock autolock(motion_buffer_lock_);
 
   if (!device_motion_buffer_)
     return;
 
@@ skipping 85 matching lines @@
                           device_sensors_.obj(),
                           static_cast<jint>(event_type));
 }
 
 int SensorManagerAndroid::GetNumberActiveDeviceMotionSensors() {
   DCHECK(!device_sensors_.is_null());
   return Java_DeviceSensors_getNumberActiveDeviceMotionSensors(
       AttachCurrentThread(), device_sensors_.obj());
 }
 
+bool SensorManagerAndroid::isUsingBackupSensorsForOrientation() {
+  DCHECK(!device_sensors_.is_null());
+  return Java_DeviceSensors_isUsingBackupSensorsForOrientation(
+      AttachCurrentThread(), device_sensors_.obj());
+}
 
 // ----- Shared memory API methods
 
 // --- Device Light
 
 bool SensorManagerAndroid::StartFetchingDeviceLightData(
     DeviceLightHardwareBuffer* buffer) {
   DCHECK(buffer);
   {
     base::AutoLock autolock(light_buffer_lock_);
@@ skipping 115 matching lines @@
 
   {
     base::AutoLock autolock(orientation_buffer_lock_);
     // If Start() was unsuccessful then set the buffer ready flag to true
     // to start firing all-null events.
     SetOrientationBufferReadyStatus(!success);
   }
 
   if (!success)
     updateRotationVectorHistogram(false);
+  else
+    is_using_backup_sensors_for_orientation_ =
+        isUsingBackupSensorsForOrientation();
 
   return success;
 }
 
 void SensorManagerAndroid::StopFetchingDeviceOrientationData() {
   Stop(kTypeOrientation);
   {
     base::AutoLock autolock(orientation_buffer_lock_);
     if (device_orientation_buffer_) {
       SetOrientationBufferReadyStatus(false);
       device_orientation_buffer_ = NULL;
     }
   }
 }
 
 }  // namespace content