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

third_party/WebKit/Source/modules/sensor/SensorProviderProxy.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/SensorProviderProxy.h"
 
+#include "core/dom/ExecutionContext.h"
+#include "modules/permissions/PermissionUtils.h"
 #include "modules/sensor/SensorProxy.h"
 #include "modules/sensor/SensorReading.h"
 #include "platform/mojo/MojoHelper.h"
 #include "public/platform/InterfaceProvider.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 // SensorProviderProxy
 SensorProviderProxy::SensorProviderProxy(LocalFrame* frame) {
@@ skipping 18 matching lines @@
   return result;
 }
 
 SensorProviderProxy::~SensorProviderProxy() {}
 
 DEFINE_TRACE(SensorProviderProxy) {
   visitor->trace(m_sensors);
   Supplement<LocalFrame>::trace(visitor);
 }
 
+void SensorProviderProxy::onPermissionServiceConnectionError() {
+  if (!Platform::current()) {
+    // TODO(rockot): Clean this up once renderer shutdown sequence is fixed.
+    return;
+  }
+
+  m_permissionService.reset();
+  for (SensorProxy* sensor : m_sensors) {
+    sensor->handleSensorError(SecurityError,
+                              "Permission service not available.");
+  }
+}
+
 SensorProxy* SensorProviderProxy::createSensor(
     device::mojom::blink::SensorType type,
+    ExecutionContext* context,
     std::unique_ptr<SensorReadingFactory> readingFactory) {
   DCHECK(!getSensor(type));
 
-  SensorProxy* sensor = new SensorProxy(type, this, std::move(readingFactory));
-  m_sensors.add(sensor);
+  // Get permission service.
+  if (!m_permissionService &&
+      connectToPermissionService(context,
+                                 mojo::GetProxy(&m_permissionService))) {
+    m_permissionService.set_connection_error_handler(convertToBaseCallback(
+        WTF::bind(&SensorProviderProxy::onPermissionServiceConnectionError,
+                  wrapWeakPersistent(this))));
 
-  return sensor;
+    RefPtr<SecurityOrigin> origin = context->getSecurityOrigin();
+    DCHECK(origin);
+    SensorProxy* sensor =
+        new SensorProxy(type, m_permissionService.get(), origin, this,
+                        std::move(readingFactory));
+    m_sensors.add(sensor);
+    return sensor;
+  }
+
+  return nullptr;

[Mikhail, 2016/11/18 12:37:42]

createSensor should not return nullptr, if there is a fatal error inside
SensorProviderProxy it has a dedicated handler (onSensorProviderConnectionError
-could be renamed to become more generic) for this.

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

OK, reusing onSensorProviderConnectionError for permission connection failures
also.

 }
 
 SensorProxy* SensorProviderProxy::getSensor(
     device::mojom::blink::SensorType type) {
   for (SensorProxy* sensor : m_sensors) {
     // TODO(Mikhail) : Hash sensors by type for efficiency.
     if (sensor->type() == type)
       return sensor;
   }
 
   return nullptr;
 }
 
 void SensorProviderProxy::onSensorProviderConnectionError() {
   if (!Platform::current()) {
     // TODO(rockot): Clean this up once renderer shutdown sequence is fixed.
     return;
   }
 
   m_sensorProvider.reset();
   for (SensorProxy* sensor : m_sensors)
     sensor->handleSensorError();
 }
 
 }  // namespace blink