Fix the leak of the wrapper created by WrapperClass_Allocate().

content/renderer/pepper/plugin_object.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/pepper/plugin_object.h"
 
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 25 matching lines @@
 const char kInvalidValueException[] = "Error: Invalid value";
 
 // NPObject implementation in terms of PPP_Class_Deprecated --------------------
 
 NPObject* WrapperClass_Allocate(NPP npp, NPClass* unused) {
   return PluginObject::AllocateObjectWrapper();
 }
 
 void WrapperClass_Deallocate(NPObject* np_object) {
   PluginObject* plugin_object = PluginObject::FromNPObject(np_object);
-  if (!plugin_object)
-    return;
-  plugin_object->ppp_class()->Deallocate(plugin_object->ppp_class_data());
-  delete plugin_object;
+  if (plugin_object) {
+    plugin_object->ppp_class()->Deallocate(plugin_object->ppp_class_data());
+    delete plugin_object;
+  }
+  delete np_object;

[brettw, 2014/06/16 19:36:50]

Sorry I don't have in my head how this is supposed to work, but this probably
means we need some more comments here. I don't understand why we need to delete
the np_object when FromNPObject fails, and not when it succeeds. And actually, I
don't understand why it might fail in the first place. Does this happen in
practice?

[Lei Zhang, 2014/06/16 20:37:30]

I'm not deleting it when FromNPObject() fails. I'm always deleting it.

WrapperClass_Allocate() above calls PluginObject::AllocateObjectWrapper() which
allocates a NPObject*, but I don't see any place that's deleting it. It comes up
when I run browser_tests under LSAN locally, and it reports the object returned
by WrapperClass_Allocate() as being leaked.

 }
 
 void WrapperClass_Invalidate(NPObject* object) {}
 
 bool WrapperClass_HasMethod(NPObject* object, NPIdentifier method_name) {
   NPObjectAccessorWithIdentifier accessor(object, method_name, false);
   if (!accessor.is_valid())
     return false;
 
   PPResultAndExceptionToNPResult result_converter(
@@ skipping 296 matching lines @@
 }
 
 // static
 NPObject* PluginObject::AllocateObjectWrapper() {
   NPObjectWrapper* wrapper = new NPObjectWrapper;
   memset(wrapper, 0, sizeof(NPObjectWrapper));
   return wrapper;
 }
 
 }  // namespace content