[Sensors] Read-only access to the sensors shared buffer from Blink

device/generic_sensor/platform_sensor_provider_base.cc

 // 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 "device/generic_sensor/platform_sensor_provider_base.h"
 
 #include <utility>
 
 #include "base/stl_util.h"
 #include "device/generic_sensor/public/interfaces/sensor_provider.mojom.h"
@@ skipping 69 matching lines @@
   sensor_map_.erase(type);
 
   if (sensor_map_.empty())
     shared_buffer_handle_.reset();
 }
 
 mojo::ScopedSharedBufferHandle
 PlatformSensorProviderBase::CloneSharedBufferHandle() {
   DCHECK(CalledOnValidThread());
   CreateSharedBufferIfNeeded();
-  return shared_buffer_handle_->Clone();
+  return shared_buffer_handle_->Clone(
+      mojo::SharedBufferHandle::AccessMode::READ_ONLY);
 }
 
 void PlatformSensorProviderBase::NotifySensorCreated(
     mojom::SensorType type,
     scoped_refptr<PlatformSensor> sensor) {
   DCHECK(CalledOnValidThread());
   DCHECK(!ContainsKey(sensor_map_, type));
   DCHECK(ContainsKey(requests_map_, type));
 
   if (sensor)
     sensor_map_[type] = sensor.get();
 
   // Inform subscribers about the sensor.
   // |sensor| can be nullptr here.
   auto it = requests_map_.find(type);
   for (auto& callback : it->second)
     callback.Run(sensor);
 
   requests_map_.erase(type);
 }
 
 }  // namespace device