[DevTools] Account for host device pixel ratio in Device Mode screenshots

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

 // Copyright 2015 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.
 /**
  * @unrestricted
  */
 Emulation.DeviceModeView = class extends UI.VBox {
   constructor() {
     super(true);
     this.setMinimumSize(150, 150);
@@ skipping 354 matching lines @@
   async captureScreenshot() {
     SDK.DOMModel.muteHighlight();
     var screenshot = await this._model.captureScreenshot(false);
     SDK.DOMModel.unmuteHighlight();
     if (screenshot === null)
       return;
 
     var pageImage = new Image();
     pageImage.src = 'data:image/png;base64,' + screenshot;
     pageImage.onload = async () => {
-      var scale = 1 / this._model.scale();
+      var scale = window.devicePixelRatio / this._model.scale();
       var outlineRect = this._model.outlineRect().scale(scale);
       var screenRect = this._model.screenRect().scale(scale);
       var visiblePageRect = this._model.visiblePageRect().scale(scale);
       var contentLeft = screenRect.left + visiblePageRect.left - outlineRect.left;
       var contentTop = screenRect.top + visiblePageRect.top - outlineRect.top;
 
       var canvas = createElement('canvas');
       canvas.width = Math.floor(outlineRect.width);
       canvas.height = Math.floor(outlineRect.height);
       var ctx = canvas.getContext('2d');
@@ skipping 160 matching lines @@
     return Promise.resolve();
   }
 
   /**
    * @param {number} size
    */
   _onMarkerClick(size) {
     this._applyCallback.call(null, size);
   }
 };