bindings,devtools: Shows DOM attributes' values in DevTools.

Source/core/inspector/InjectedScriptSource.js

Index: Source/core/inspector/InjectedScriptSource.js
diff --git a/Source/core/inspector/InjectedScriptSource.js b/Source/core/inspector/InjectedScriptSource.js
index 234c0a831a3eb73c6ac57de6a3ba89256daebddb..c05775eeefc6827a42274c21dc7061619028400d 100644
--- a/Source/core/inspector/InjectedScriptSource.js
+++ b/Source/core/inspector/InjectedScriptSource.js
@@ -220,6 +220,36 @@ function indexOf(str, searchElement, fromIndex)
 }
 
 /**
+ * DOM Attributes which have observable side effect on getter, in the form of
+ *   {interfaceName1: {attributeName1: true,
+ *                     attributeName2: true,
+ *                     ...},
+ *    interfaceName2: {...},
+ *    ...}
+ * @type {!Object<string, !Object<string, boolean>>}
+ * @const
+ */
+var domAttributesWithObservableSideEffectOnGet = InjectedScriptHost.getDOMAttributesWithObservableSideEffectOnGet();

[pfeldman, 2015/03/09 11:41:41]

var domAttributesWithObservableSideEffectOnGet = nullifyObjectProto({});
domAttributesWithObservableSideEffectOnGet["Request"] = nullifyObjectProto({});
domAttributesWithObservableSideEffectOnGet["Request"]["body"] = true;

[Yuki, 2015/03/09 12:48:13]

Done.

+
+/**
+ * @param {!Object} object
+ * @param {!string} attribute
+ * @return {boolean}
+ */
+function doesAttributeHaveObservableSideEffectOnGet(object, attribute)
+{
+    for (var interfaceName in domAttributesWithObservableSideEffectOnGet) {
+        var isInstance = InjectedScriptHost.suppressWarningsAndCallFunction(function(object, interfaceName) {
+            return typeof window[interfaceName] === "function" && object instanceof window[interfaceName];

[pfeldman, 2015/03/09 11:41:41]

This is no better than what it used to be as long as we are fetching the
window[interfaceName]. Page can easily override it. Our options are:

1) not care about it at all, which might lead to a new devtools detection
technique
2) fix it as I was suggesting via returning the canonical types from the
bindings:

var types = InjectedScriptHost.canonicalTypes(object); // returns ["Request",
"Object"]
for (var i = 0; i < types.length; ++i) {
    if (domAttrsWithSideEffects[types[i]] &&
domAttrsWithSideEffects[types[i]][attribute])
        return true;
}
return false;

[Yuki, 2015/03/09 12:48:13]

I prefer option 1.  I don't think it's worth creating a new mechanism to
retrieve class inheritance info as string, which we don't have for now.

We already check that the given object is a DOM wrapper.  I think it's enough.

+        }, null, [object, interfaceName]);
+        if (isInstance) {
+            return attribute in domAttributesWithObservableSideEffectOnGet[interfaceName];
+        }
+    }
+    return false;
+}
+
+/**
  * @constructor
  */
 var InjectedScript = function()
@@ -555,7 +585,7 @@ InjectedScript.prototype = {
                     if (descriptor) {
                         if (accessorPropertiesOnly && !("get" in descriptor || "set" in descriptor))
                             continue;
-                        if ("get" in descriptor && "set" in descriptor && InjectedScriptHost.isPopularDOMObject(object) && name != "__proto__") {
+                        if ("get" in descriptor && "set" in descriptor && name != "__proto__" && InjectedScriptHost.isDOMWrapper(object) && !doesAttributeHaveObservableSideEffectOnGet(object, name)) {
                             descriptor.value = InjectedScriptHost.suppressWarningsAndCallFunction(function(attribute) { return this[attribute]; }, object, [name]);
                             delete descriptor.get;
                             delete descriptor.set;
@@ -1516,6 +1546,7 @@ InjectedScript.RemoteObject.prototype = {
 
     __proto__: null
 }
+
 /**
  * @constructor
  * @param {number} ordinal