DevTools: fix styles and input validation in sensor pane

third_party/WebKit/Source/devtools/front_end/emulation/DeviceOrientation.js

 // 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.
 
 /**
  * @constructor
  * @param {number} alpha
  * @param {number} beta
  * @param {number} gamma
  */
@@ skipping 59 matching lines @@
 
     return new WebInspector.DeviceOrientation(alpha, beta, gamma);
 }
 
 /**
  * @param {string} value
  * @return {boolean}
  */
 WebInspector.DeviceOrientation.validator = function(value)
 {
-    return !value || /^([+-]?[\d]+(\.\d+)?|[+-]?\.\d+)$/.test(value);
+    return /^([+-]?[\d]+(\.\d+)?|[+-]?\.\d+)$/.test(value);
 }