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

chrome/browser/sensor/sensor_permission_context.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 "chrome/browser/sensor/sensor_permission_context.h"
+
+#include "chrome/browser/content_settings/tab_specific_content_settings.h"
+#include "chrome/browser/permissions/permission_request_id.h"
+#include "content/public/browser/child_process_security_policy.h"
+#include "content/public/browser/permission_type.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/web_contents.h"
+#include "url/gurl.h"
+
+SensorPermissionContext::SensorPermissionContext(Profile* profile)
+    : PermissionContextBase(profile, CONTENT_SETTINGS_TYPE_SENSORS) {}
+
+SensorPermissionContext::~SensorPermissionContext() {}
+
+void SensorPermissionContext::UpdateTabContext(const PermissionRequestID& id,
+                                               const GURL& requesting_frame,
+                                               bool allowed) {
+  TabSpecificContentSettings* content_settings =
+      TabSpecificContentSettings::GetForFrame(id.render_process_id(),
+                                              id.render_frame_id());
+  if (!content_settings)
+    return;
+
+  if (allowed)
+    content_settings->OnSensorAccessed(requesting_frame);
+  else
+    content_settings->OnSensorAccessBlocked(requesting_frame);
+}
+
+bool SensorPermissionContext::IsRestrictedToSecureOrigins() const {
+  return true;
+}