[MD settings] small code health changes

chrome/browser/resources/settings/device_page/layout_behavior.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.
 
 /**
  * @fileoverview Behavior for handling display layout, specifically
  *     edge snapping and collisions.
  */
 
 /** @polymerBehavior */
@@ skipping 18 matching lines @@
   /** @private {!Map<string, chrome.system.display.DisplayLayout>} */
   displayLayoutMap_: new Map(),
 
   /**
    * The calculated bounds used for generating the div bounds.
    * @private {!Map<string, chrome.system.display.Bounds>}
    */
   calculatedBoundsMap_: new Map(),
 
   /** @private {string} */
-  dragLayoutId: '',
+  dragLayoutId_: '',
 
   /** @private {string} */
   dragParentId_: '',
 
   /** @private {!chrome.system.display.Bounds|undefined} */
   dragBounds_: undefined,
 
   /** @private {!chrome.system.display.LayoutPosition|undefined} */
   dragLayoutPosition_: undefined,
 
   /**
    * @param {!Array<!chrome.system.display.DisplayUnitInfo>} displays
    * @param {!Array<!chrome.system.display.DisplayLayout>} layouts
    */
   initializeDisplayLayout: function(displays, layouts) {
-    this.dragLayoutId = '';
+    this.dragLayoutId_ = '';
     this.dragParentId_ = '';
 
     this.mirroring = displays.length > 0 && !!displays[0].mirroringSourceId;
 
     this.displayBoundsMap_.clear();
     for (var i = 0; i < displays.length; ++i) {
       var display = displays[i];
       this.displayBoundsMap_.set(display.id, display.bounds);
     }
     this.displayLayoutMap_.clear();
@@ skipping 12 matching lines @@
   },
 
   /**
    * Called when a drag event occurs. Checks collisions and updates the layout.
    * @param {string} id
    * @param {!chrome.system.display.Bounds} newBounds The new calculated
    *     bounds for the display.
    * @return {!chrome.system.display.Bounds}
    */
   updateDisplayBounds: function(id, newBounds) {
-    this.dragLayoutId = id;
+    this.dragLayoutId_ = id;
 
     // Find the closest parent.
     var closestId = this.findClosest_(id, newBounds);
     assert(closestId);
 
     // Find the closest edge.
     var closestBounds = this.getCalculatedDisplayBounds(closestId);
     var layoutPosition =
         this.getLayoutPositionForBounds_(newBounds, closestBounds);
 
@@ skipping 28 matching lines @@
 
     return newBounds;
   },
 
   /**
    * Called when dragging ends. Sends the updated layout to chrome.
    * @param {string} id
    */
   finishUpdateDisplayBounds: function(id) {
     this.highlightEdge_('', undefined);  // Remove any highlights.
-    if (id != this.dragLayoutId || !this.dragBounds_ ||
+    if (id != this.dragLayoutId_ || !this.dragBounds_ ||
         !this.dragLayoutPosition_) {
       return;
     }
 
     var layout = this.displayLayoutMap_.get(id);
 
     var orphanIds;
     if (!layout || layout.parentId == '') {
       // Primary display. Set the calculated position to |dragBounds_|.
       this.setCalculatedDisplayBounds_(id, this.dragBounds_);
@@ skipping 557 matching lines @@
           highlight == chrome.system.display.LayoutPosition.LEFT);
       div.classList.toggle(
           'highlight-top',
           highlight == chrome.system.display.LayoutPosition.TOP);
       div.classList.toggle(
           'highlight-bottom',
           highlight == chrome.system.display.LayoutPosition.BOTTOM);
     }
   },
 };