Add Reset to ScopedClosureRunner.

base/bind_helpers.cc

Index: base/bind_helpers.cc
diff --git a/base/bind_helpers.cc b/base/bind_helpers.cc
index f2fc3bb0daaed9697a899b2e80f5322e1a074fe9..871eeefc71f04364579e335c31f70cf58746bbae 100644
--- a/base/bind_helpers.cc
+++ b/base/bind_helpers.cc
@@ -20,6 +20,12 @@ ScopedClosureRunner::~ScopedClosureRunner() {
     closure_.Run();
 }
 
+void ScopedClosureRunner::Reset(const Closure& closure) {
+  if (!closure_.is_null())

[awong, 2013/08/29 18:57:12]

Maybe follow the Release() pattern of caching the closure_ before returning?

As is, I worry that Run() could delete this ScopedClosure.

One could even do 

Closure old_closure = Release();
closure_ = closure;
if (!old_closure.is_null())
  old_closure.run();

+    closure_.Run();
+  closure_ = closure;
+}
+
 Closure ScopedClosureRunner::Release() {
   Closure result = closure_;
   closure_.Reset();