Issue 2879 - Move element selection into the content process

lib/child/utils.js

 /*
  * This Source Code is subject to the terms of the Mozilla Public License
  * version 2.0 (the "License"). You can obtain a copy of the License at
  * http://mozilla.org/MPL/2.0/.
  */
 
 "use strict";
 
 /**
  * Element creation helper, allows defining attributes and child elements in one
@@ skipping 44 matching lines @@
     result = result.defaultView.frameElement;
 
   if (result && result.nodeType != result.ELEMENT_NODE)
     return null;
 
   return result;
 }
 exports.getParentElement = getParentElement;
 
 /**
+ * Modifies a rectangle with coordinates relative to a window's client area
+ * to make sure it doesn't exceed that client area.
+ * @param {Object} rect
+ *   Rectangle with properties left, top, right, bottom.
+ * @param {Window} wnd
+ *   Window to restrict the rectangle to.
+ */
+function intersectRect(rect, wnd)
+{
+  let [wndWidth, wndHeight] = getWindowSize(wnd);
+  rect.left = Math.max(rect.left, 0);
+  rect.top = Math.max(rect.top, 0);
+  rect.right = Math.min(rect.right, wndWidth);
+  rect.bottom = Math.min(rect.bottom, wndHeight);
+}
+
+/**
  * Calculates the element's position within the top frame. This will consider
  * the element being clipped by frame boundaries.
  * @return {Object}
  *   Object with properties left, top, width, height denoting the element's
  *   position and size within the top frame.
  */
 function getElementPosition(/**Element*/ element)
 {
-  // Restrict rectangle coordinates by the boundaries of a window's client area
-  function intersectRect(rect, wnd)

[saroyanm, 2016/11/23 17:44:39]

Suggestion: This function will be created each time we will run
"getElementPosition", let's move it outside of the function.

[Wladimir Palant, 2016/11/24 14:02:02]

Done.

-  {
-    let [wndWidth, wndHeight] = getWindowSize(wnd);
-    rect.left = Math.max(rect.left, 0);
-    rect.top = Math.max(rect.top, 0);
-    rect.right = Math.min(rect.right, wndWidth);
-    rect.bottom = Math.min(rect.bottom, wndHeight);
-  }
-
   let rect = element.getBoundingClientRect();
   let wnd = element.ownerDocument.defaultView;
 
   rect = {left: rect.left, top: rect.top,
           right: rect.right, bottom: rect.bottom};
   while (true)
   {
     intersectRect(rect, wnd);
 
     if (!wnd.frameElement)
@@ skipping 10 matching lines @@
 
     rect.left += relLeft;
     rect.right += relLeft;
     rect.top += relTop;
     rect.bottom += relTop;
   }
 
   return rect;
 }
 exports.getElementPosition = getElementPosition;