Fix PrepareTextureCopyOutputResult to avoid ScopedCallbackRunner.

base/callback_helpers.cc

Index: base/callback_helpers.cc
diff --git a/base/callback_helpers.cc b/base/callback_helpers.cc
index 8fd3dde6ca49089e9e4cc66e0089706f902ae678..bcd2396a04040a837a595eb455ec927c65ea1a9d 100644
--- a/base/callback_helpers.cc
+++ b/base/callback_helpers.cc
@@ -5,6 +5,7 @@
 #include "base/callback_helpers.h"
 
 #include "base/callback.h"
+#include "base/logging.h"
 
 namespace base {
 
@@ -23,17 +24,18 @@ ScopedClosureRunner::ScopedClosureRunner(ScopedClosureRunner&& other)
 
 ScopedClosureRunner& ScopedClosureRunner::operator=(
     ScopedClosureRunner&& other) {
-  Reset(other.Release());
+  DCHECK(closure_.is_null());
+  ReplaceClosure(other.Release());
   return *this;
 }
 
-void ScopedClosureRunner::Reset() {
+void ScopedClosureRunner::RunNow() {
   Closure old_closure = Release();
   if (!old_closure.is_null())
     old_closure.Run();
 }
 
-void ScopedClosureRunner::Reset(const Closure& closure) {
+void ScopedClosureRunner::ReplaceClosure(const Closure& closure) {
   Closure old_closure = Release();
   closure_ = closure;
   if (!old_closure.is_null())