[Sensors] Error handler in Senor class should stop the platform sensor

third_party/WebKit/Source/modules/sensor/Sensor.cpp

Index: third_party/WebKit/Source/modules/sensor/Sensor.cpp
diff --git a/third_party/WebKit/Source/modules/sensor/Sensor.cpp b/third_party/WebKit/Source/modules/sensor/Sensor.cpp
index 9f3de1ce7116d82559c6c0eec76461218cb750b4..8f3a766d112d1e67e1596f21b968387dc80afb91 100644
--- a/third_party/WebKit/Source/modules/sensor/Sensor.cpp
+++ b/third_party/WebKit/Source/modules/sensor/Sensor.cpp
@@ -58,24 +58,10 @@ Sensor::Sensor(ExecutionContext* execution_context,
 Sensor::~Sensor() = default;
 
 void Sensor::start() {
-  if (state_ != Sensor::SensorState::kIdle)
-    return;
-
-  InitSensorProxyIfNeeded();
-  if (!sensor_proxy_) {
-    ReportError(kInvalidStateError,
-                "The Sensor is no longer associated to a frame.");
-    return;
-  }
-
-  last_update_timestamp_ = WTF::MonotonicallyIncreasingTime();
   StartListening();
 }
 
 void Sensor::stop() {
-  if (state_ == Sensor::SensorState::kIdle)
-    return;
-
   StopListening();
 }
 
@@ -166,16 +152,14 @@ void Sensor::InitSensorProxyIfNeeded() {
 }
 
 void Sensor::ContextDestroyed(ExecutionContext*) {
-  if (state_ == Sensor::SensorState::kActivated ||
-      state_ == Sensor::SensorState::kActivating)
-    StopListening();
+  StopListening();
 }
 
 void Sensor::OnSensorInitialized() {
   if (state_ != Sensor::SensorState::kActivating)
     return;
 
-  StartListening();
+  RequestAddConfiguration();
 }
 
 void Sensor::NotifySensorChanged(double timestamp) {
@@ -194,78 +178,92 @@ void Sensor::NotifySensorChanged(double timestamp) {
 void Sensor::OnSensorError(ExceptionCode code,
                            const String& sanitized_message,
                            const String& unsanitized_message) {
-  ReportError(code, sanitized_message, unsanitized_message);
+  HandleError(code, sanitized_message, unsanitized_message);
 }
 
-void Sensor::OnStartRequestCompleted(bool result) {
+void Sensor::OnAddConfigurationRequestCompleted(bool result) {
   if (state_ != SensorState::kActivating)
     return;
 
   if (!result) {
-    ReportError(kNotReadableError, "start() call has failed.");
+    HandleError(kNotReadableError, "start() call has failed.");
     return;
   }
 
+  // The initial value for m_lastUpdateTimestamp is set to current time,
+  // so that the first reading update will be notified considering the given
+  // frequency hint.
+  last_update_timestamp_ = WTF::MonotonicallyIncreasingTime();
+
   UpdateState(Sensor::SensorState::kActivated);
+
+  if (GetExecutionContext()) {
+    TaskRunnerHelper::Get(TaskType::kSensor, GetExecutionContext())
+        ->PostTask(BLINK_FROM_HERE, WTF::Bind(&Sensor::NotifyOnActivate,
+                                              WrapWeakPersistent(this)));
+  }
 }
 
 void Sensor::StartListening() {
-  DCHECK(sensor_proxy_);
-  UpdateState(Sensor::SensorState::kActivating);
+  if (state_ != SensorState::kIdle)
+    return;
 
-  sensor_proxy_->AddObserver(this);
-  if (!sensor_proxy_->IsInitialized()) {
-    sensor_proxy_->Initialize();
+  InitSensorProxyIfNeeded();
+  if (!sensor_proxy_) {
+    HandleError(kInvalidStateError,
+                "The Sensor is no longer associated to a frame.");
     return;
   }
 
-  if (!configuration_) {
-    configuration_ = CreateSensorConfig();
-    DCHECK(configuration_);
-    DCHECK(configuration_->frequency > 0 &&
-           configuration_->frequency <=
-               SensorConfiguration::kMaxAllowedFrequency);
+  if (sensor_proxy_->IsInitialized()) {
+    RequestAddConfiguration();
+  } else {
+    sensor_proxy_->Initialize();
   }

[Reilly Grant (use Gerrit), 2017/04/26 14:58:45]

nit: no braces when both if and else clauses are a single line.

[Mikhail, 2017/04/27 07:50:34]

Done.

 
-  auto start_callback =
-      WTF::Bind(&Sensor::OnStartRequestCompleted, WrapWeakPersistent(this));
-  sensor_proxy_->AddConfiguration(configuration_->Clone(),
-                                  std::move(start_callback));
+  sensor_proxy_->AddObserver(this);
+  UpdateState(SensorState::kActivating);
 }
 
 void Sensor::StopListening() {
-  DCHECK(sensor_proxy_);
-  UpdateState(Sensor::SensorState::kIdle);
+  if (state_ == SensorState::kIdle)
+    return;
 
+  DCHECK(sensor_proxy_);
   if (sensor_proxy_->IsInitialized()) {
     DCHECK(configuration_);
     sensor_proxy_->RemoveConfiguration(configuration_->Clone());
   }
+
   sensor_proxy_->RemoveObserver(this);
+  UpdateState(Sensor::SensorState::kIdle);
 }
 
-void Sensor::UpdateState(Sensor::SensorState new_state) {
-  if (new_state == state_)
-    return;
-
-  if (new_state == SensorState::kActivated && GetExecutionContext()) {
-    DCHECK_EQ(SensorState::kActivating, state_);
-    // The initial value for m_lastUpdateTimestamp is set to current time,
-    // so that the first reading update will be notified considering the given
-    // frequency hint.
-    last_update_timestamp_ = WTF::MonotonicallyIncreasingTime();
-    TaskRunnerHelper::Get(TaskType::kSensor, GetExecutionContext())
-        ->PostTask(BLINK_FROM_HERE, WTF::Bind(&Sensor::NotifyOnActivate,
-                                              WrapWeakPersistent(this)));
+void Sensor::RequestAddConfiguration() {
+  if (!configuration_) {
+    configuration_ = CreateSensorConfig();
+    DCHECK(configuration_);
+    DCHECK(configuration_->frequency > 0 &&
+           configuration_->frequency <=
+               SensorConfiguration::kMaxAllowedFrequency);
   }
 
+  auto start_callback = WTF::Bind(&Sensor::OnAddConfigurationRequestCompleted,

[Reilly Grant (use Gerrit), 2017/04/26 14:58:45]

nit: no need to save the callback in a local variable before passing it to
sensor_proxy_->AddConfiguration().

[Mikhail, 2017/04/27 07:50:34]

Done.

+                                  WrapWeakPersistent(this));
+  DCHECK(sensor_proxy_);
+  sensor_proxy_->AddConfiguration(configuration_->Clone(),
+                                  std::move(start_callback));
+}
+
+void Sensor::UpdateState(Sensor::SensorState new_state) {
   state_ = new_state;
 }
 
-void Sensor::ReportError(ExceptionCode code,
+void Sensor::HandleError(ExceptionCode code,
                          const String& sanitized_message,
                          const String& unsanitized_message) {
-  UpdateState(SensorState::kIdle);
+  StopListening();
+
   if (GetExecutionContext()) {
     auto error =
         DOMException::Create(code, sanitized_message, unsanitized_message);