On Linux, move the passing of filedescriptors to a dedicated socketpair().

chrome/tools/test/reference_build/chrome_linux/resources/inspector/treeoutline.js

Index: chrome/tools/test/reference_build/chrome_linux/resources/inspector/treeoutline.js
diff --git a/chrome/tools/test/reference_build/chrome_linux/resources/inspector/treeoutline.js b/chrome/tools/test/reference_build/chrome_linux/resources/inspector/treeoutline.js
index 579e7fb030540fdc5f39f251d7935fbfa8211318..ecc322b9725f6149a5bc315a190c11e19321d701 100644
--- a/chrome/tools/test/reference_build/chrome_linux/resources/inspector/treeoutline.js
+++ b/chrome/tools/test/reference_build/chrome_linux/resources/inspector/treeoutline.js
@@ -249,35 +249,40 @@ TreeOutline.prototype._forgetChildrenRecursive = function(parentElement)
     }
 }
 
-TreeOutline.prototype.findTreeElement = function(representedObject, isAncestor, getParent, equal)
+TreeOutline.prototype.getCachedTreeElement = function(representedObject)
 {
     if (!representedObject)
         return null;
 
-    if (!equal)
-        equal = function(a, b) { return a === b };
-
     if ("__treeElementIdentifier" in representedObject) {
         // If this representedObject has a tree element identifier, and it is a known TreeElement
         // in our tree we can just return that tree element.
         var elements = this._knownTreeElements[representedObject.__treeElementIdentifier];
         if (elements) {
             for (var i = 0; i < elements.length; ++i)
-                if (equal(elements[i].representedObject, representedObject))
+                if (elements[i].representedObject === representedObject)
                     return elements[i];
         }
     }
+    return null;
+}
 
-    if (!isAncestor || !(isAncestor instanceof Function) || !getParent || !(getParent instanceof Function))
+TreeOutline.prototype.findTreeElement = function(representedObject, isAncestor, getParent)
+{
+    if (!representedObject)
         return null;
 
+    var cachedElement = this.getCachedTreeElement(representedObject);
+    if (cachedElement)
+        return cachedElement;
+
     // The representedObject isn't know, so we start at the top of the tree and work down to find the first
     // tree element that represents representedObject or one of its ancestors.
     var item;
     var found = false;
     for (var i = 0; i < this.children.length; ++i) {
         item = this.children[i];
-        if (equal(item.representedObject, representedObject) || isAncestor(item.representedObject, representedObject)) {
+        if (item.representedObject === representedObject || isAncestor(item.representedObject, representedObject)) {
             found = true;
             break;
         }
@@ -292,7 +297,7 @@ TreeOutline.prototype.findTreeElement = function(representedObject, isAncestor,
     var currentObject = representedObject;
     while (currentObject) {
         ancestors.unshift(currentObject);
-        if (equal(currentObject, item.representedObject))
+        if (currentObject === item.representedObject)
             break;
         currentObject = getParent(currentObject);
     }
@@ -301,18 +306,16 @@ TreeOutline.prototype.findTreeElement = function(representedObject, isAncestor,
     for (var i = 0; i < ancestors.length; ++i) {
         // Make sure we don't call findTreeElement with the same representedObject
         // again, to prevent infinite recursion.
-        if (equal(ancestors[i], representedObject))
+        if (ancestors[i] === representedObject)
             continue;
         // FIXME: we could do something faster than findTreeElement since we will know the next
         // ancestor exists in the tree.
-        item = this.findTreeElement(ancestors[i], isAncestor, getParent, equal);
+        item = this.findTreeElement(ancestors[i], isAncestor, getParent);
         if (item && item.onpopulate)
             item.onpopulate(item);
     }
 
-    // Now that all the ancestors are populated, try to find the representedObject again. This time
-    // without the isAncestor and getParent functions to prevent an infinite recursion if it isn't found.
-    return this.findTreeElement(representedObject, null, null, equal);
+    return this.getCachedTreeElement(representedObject);
 }
 
 TreeOutline.prototype.treeElementFromPoint = function(x, y)