Remove task.h and finish base::Bind() migration.

base/bind_helpers.h

 // 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.
 
 // This defines a set of argument wrappers and related factory methods that
 // can be used specify the refcounting and reference semantics of arguments
 // that are bound by the Bind() function in base/bind.h.
 //
-// The public functions are base::Unretained(), base::Owned(), bass::Passed(),
+// It also defines a set of simple functions and utilities that people want
+// when using Callback<> and Bind().
+//
+//
+// ARGUMENT BINDING WRAPPERS
+//
+// The wrapper functions are base::Unretained(), base::Owned(), bass::Passed(),
 // base::ConstRef(), and base::IgnoreResult().
 //
 // Unretained() allows Bind() to bind a non-refcounted class, and to disable
 // refcounting on arguments that are refcounted objects.
 //
 // Owned() transfers ownership of an object to the Callback resulting from
 // bind; the object will be deleted when the Callback is deleted.
 //
 // Passed() is for transferring movable-but-not-copyable types (eg. scoped_ptr)
 // through a Callback. Logically, this signifies a destructive transfer of
@@ skipping 97 matching lines @@
 //
 //   // |arg| in TakesOwnership() is given ownership of Foo(). |cb|
 //   // no longer owns Foo() and, if reset, would not delete Foo().
 //   cb.Run();  // Foo() is now transferred to |arg| and deleted.
 //   cb.Run();  // This CHECK()s since Foo() already been used once.
 //
 // Passed() is particularly useful with PostTask() when you are transferring
 // ownership of an argument into a task, but don't necessarily know if the
 // task will always be executed. This can happen if the task is cancellable
 // or if it is posted to a MessageLoopProxy.
+//
+//
+// SIMPLE FUNCTIONS AND UTILITIES.
+//
+//   DoNothing() - Useful for creating a Closure that does nothing when called.
+//   DeletePointer<T>() - Useful for creating a Closure that will delete a
+//                        pointer when invoked. Only use this when necessary.
+//                        In most cases MessageLoop::DeleteSoon() is a better
+//                        fit.
+//   ScopedClosureRunner - Scoper objec that runs the wrapped closure when it

[James Hawkins, 2012/01/06 21:15:34]

s/objec/object/

+//                         goes out of scope. It's conceptually similar to
+//                         scoped_ptr<> but calls Run() instead of deleting
+//                         the pointer.
 
 #ifndef BASE_BIND_HELPERS_H_
 #define BASE_BIND_HELPERS_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "base/template_util.h"
 
@@ skipping 373 matching lines @@
 static inline internal::IgnoreResultHelper<T> IgnoreResult(T data) {
   return internal::IgnoreResultHelper<T>(data);
 }
 
 template <typename T>
 static inline internal::IgnoreResultHelper<Callback<T> >
 IgnoreResult(const Callback<T>& data) {
   return internal::IgnoreResultHelper<Callback<T> >(data);
 }
 
+BASE_EXPORT void DoNothing();
+
+template<typename T>
+void DeletePointer(T* obj) {
+  delete obj;
+}
+
+// ScopedClosureRunner is akin to scoped_ptr for Closures. It ensures that the
+// Closure is executed and deleted no matter how the current scope exits.
+class BASE_EXPORT ScopedClosureRunner {
+ public:
+  explicit ScopedClosureRunner(const Closure& closure);
+  ~ScopedClosureRunner();
+
+  Closure Release();
+
+ private:
+  Closure closure_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(ScopedClosureRunner);
+};
+
 }  // namespace base
 
 #endif  // BASE_BIND_HELPERS_H_