Force non overlay scrollbar in Devtools/Performance for Aura Overlay Scrollbar

third_party/WebKit/Source/devtools/front_end/ui/UIUtils.js

Index: third_party/WebKit/Source/devtools/front_end/ui/UIUtils.js
diff --git a/third_party/WebKit/Source/devtools/front_end/ui/UIUtils.js b/third_party/WebKit/Source/devtools/front_end/ui/UIUtils.js
index d952835790792d5407b3e3abc269ce4a9fd56e7b..ea0a021fb2e34331e953b1e088d703fb9b721d85 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui/UIUtils.js
+++ b/third_party/WebKit/Source/devtools/front_end/ui/UIUtils.js
@@ -669,6 +669,24 @@ UI.installComponentRootStyles = function(element) {
   UI.appendStyle(element, 'ui/inspectorCommon.css');
   UI.themeSupport.injectHighlightStyleSheets(element);
   element.classList.add('platform-' + Host.platform());
+
+  /**
+   * Detect overlay scrollbar enable by checking clientWidth and offsetWidth of
+   * overflow: scroll div.
+   * @param {?Document=} document
+   * @return {boolean}
+   */
+  function overlayScrollbarEnabled(document) {
+    var scrollDiv = document.createElement('div');
+    scrollDiv.setAttribute('style', 'width: 100px; height: 100px; overflow: scroll;');
+    document.body.appendChild(scrollDiv);
+    var scrollbarWidth = scrollDiv.offsetWidth - scrollDiv.clientWidth;
+    document.body.removeChild(scrollDiv);
+    return scrollbarWidth === 0;
+  }
+
+  if (!Host.isMac() && overlayScrollbarEnabled(element.ownerDocument))
+    element.classList.add('overlay-scrollbar-enabled');
 };
 
 /**