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

Source/core/inspector/InjectedScriptSource.js

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 537 matching lines @@
                 var name = property;
                 if (isSymbol(property))
                     name = injectedScript._describe(property);
 
                 try {
                     propertyProcessed[property] = true;
                     var descriptor = nullifyObjectProto(InjectedScriptHost.suppressWarningsAndCallFunction(Object.getOwnPropertyDescriptor, Object, [o, property]));
                     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.isDOMAttributeWithNoSideEffect(object, name)) {

[haraken, 2015/03/05 15:14:26]

If pfeldman@ is fine, IMHO, we should do the blacklisting in JS instead of C++,
because JS-side blacklisting would be much simpler and thus safer (this CL
introduces a bunch of complicated logic to C++). For example, we can create a
helper function like:

  function isDOMAttributeWithNoSideEffect(object, name) {
    if (object instanceof Request && name == "body")
      return false;
    if (object instanceof Response && name == "body")
      return false;
    return true;
  }

If it is not acceptable, I'm OK with the current approach.

[pfeldman, 2015/03/05 17:42:54]

I'm fine with it as long as the instanceof Request / Response is implemented in
the bindings.

[haraken, 2015/03/06 02:29:19]

If we want to implement the instanceof Request/Response in bindings/, we need to
implement it in C++, resulting in this CL...

One way to avoid the complexity would be to implement
InjectedScriptHost.isDOMAttributeWithNoSideEffect in Blink-in-JS. Then we can
put it in bindings/ but can write the logic in JS. This might be worth doing,
because we can move a lot of complicated existing C++ in
V8InjectedScriptHostCustom.cpp to the JS as well.

Jens?

                             descriptor.value = InjectedScriptHost.suppressWarningsAndCallFunction(function(attribute) { return this[attribute]; }, object, [name]);
                             delete descriptor.get;
                             delete descriptor.set;
                         }
                     } else {
                         // Not all bindings provide proper descriptors. Fall back to the writable, configurable property.
                         if (accessorPropertiesOnly)
                             continue;
                         try {
                             descriptor = { name: name, value: o[property], writable: false, configurable: false, enumerable: false, __proto__: null };
@@ skipping 1360 matching lines @@
      */
     _logEvent: function(event)
     {
         inspectedWindow.console.log(event.type, event);
     }
 }
 
 injectedScript._commandLineAPIImpl = new CommandLineAPIImpl();
 return injectedScript;
 })