Decouple VR Shell DPR and CSS size from Physical Displays.

chrome/browser/resources/vr_shell/vr_shell_ui.js

Index: chrome/browser/resources/vr_shell/vr_shell_ui.js
diff --git a/chrome/browser/resources/vr_shell/vr_shell_ui.js b/chrome/browser/resources/vr_shell/vr_shell_ui.js
index 68e9d935e90b6d19f4362d2e5fb4ecc6de2c6568..1e5d1f243ea29cea1ab6ed558af4dccfd52c6643 100644
--- a/chrome/browser/resources/vr_shell/vr_shell_ui.js
+++ b/chrome/browser/resources/vr_shell/vr_shell_ui.js
@@ -10,7 +10,6 @@ var vrShellUi = (function() {
 
   let uiRootElement = document.querySelector('#ui');
   let uiStyle = window.getComputedStyle(uiRootElement);
-  let scaleFactor = uiStyle.getPropertyValue('--scaleFactor');
   /** @const */ var ANIM_DURATION = 150;
 
   function getStyleFloat(style, property) {
@@ -70,8 +69,7 @@ var vrShellUi = (function() {
       let pixelHeight = Math.ceil(rect.bottom) - pixelY;
 
       let element = new api.UiElement(pixelX, pixelY, pixelWidth, pixelHeight);
-      element.setSize(scaleFactor * pixelWidth / 1000,
-          scaleFactor * pixelHeight / 1000);
+      element.setSize(pixelWidth / 1000, pixelHeight / 1000);
 
       // Pull additional custom properties from CSS.
       let style = window.getComputedStyle(domElement);
@@ -414,6 +412,9 @@ var vrShellUi = (function() {
       this.controls.setEnabled(mode == api.Mode.STANDARD && !menuMode);
       this.omnibox.setEnabled(mode == api.Mode.STANDARD && !menuMode);
       this.secureOriginWarnings.setEnabled(mode == api.Mode.WEB_VR);
+
+      let uiElement = document.querySelector('#ui');

[bshe, 2016/11/30 23:00:46]

nit: use uiRootElement directly?

[mthiesse, 2016/11/30 23:25:05]

Done.

+      api.setUiCssSize(uiElement.clientWidth, uiElement.clientHeight, 1.0);
     }
 
     setSecureOrigin(secure) {