[sensors] Add Permission guard to the generic sensor apis.

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

 // Copyright 2016 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 "modules/sensor/Sensor.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContextTask.h"
 #include "core/inspector/ConsoleMessage.h"
@@ skipping 149 matching lines @@
     return;
 
   Document* document = toDocument(getExecutionContext());
   if (!document || !document->frame())
     return;
 
   auto provider = SensorProviderProxy::from(document->frame());
   m_sensorProxy = provider->getSensor(m_type);
 
   if (!m_sensorProxy) {
-    m_sensorProxy =
-        provider->createSensor(m_type, createSensorReadingFactory());
+    m_sensorProxy = provider->createSensor(m_type, getExecutionContext(),
+                                           createSensorReadingFactory());
+    // check if proxy was created correctly.
+    if (!m_sensorProxy)

[shalamov, 2016/11/18 13:17:45]

This is sync operation that is initiated from Sensor::start, so, start will
throw exception (InvalidStateError) and this check will throw async error
NotAllowedError. Looks strange, can we just throw one exception?

[riju_, 2016/11/21 11:23:28]

Done.

+      reportError(NotAllowedError, "Could not create sensor proxy.");
   }
 }
 
 void Sensor::contextDestroyed() {
   if (m_state == Sensor::SensorState::Active ||
       m_state == Sensor::SensorState::Activating)
     stopListening();
 }
 
 void Sensor::onSensorInitialized() {
@@ skipping 168 matching lines @@
 void Sensor::notifyOnActivate() {
   dispatchEvent(Event::create(EventTypeNames::activate));
 }
 
 void Sensor::notifyError(DOMException* error) {
   dispatchEvent(
       SensorErrorEvent::create(EventTypeNames::error, std::move(error)));
 }
 
 }  // namespace blink