Create a thread-safe observer list. Will be used

by SystemMonitor.

Right now the class requires that Observers be RefCounted<>.  This is because we invoke tasks via NewRunnableMethod for them.  However, because we manually track lifecycle via AddObserver/RemoveObserver, we could override the RunnableMethodTraits to not require RefCounted<>.   This would have the advantage that callers do not need to make all Observers be RefCounted, but makes it more critical that observers not forget to call RemoveObserver().
Review URL: http://codereview.chromium.org/7353

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@3787 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 14 insertions, 0 deletions

diff --git a/base/task.h b/base/task.h
index 8db4560..9d4e6e2 100644
--- a/base/task.h
+++ b/base/task.h
@@ -625,5 +625,19 @@ typename Callback5<Arg1, Arg2, Arg3, Arg4, Arg5>::Type* NewCallback(
       Tuple5<Arg1, Arg2, Arg3, Arg4, Arg5> >(object, method);
 }
 
+// An UnboundMethod is a wrapper for a method where the actual object is
+// provided at Run dispatch time.
+template <class T, class Method, class Params>
+class UnboundMethod {
+ public:
+  UnboundMethod(Method m, Params p) : m_(m), p_(p) {}
+  void Run(T* obj) const {
+    DispatchToMethod(obj, m_, p_);
+  }
+ private:
+  Method m_;
+  Params p_;
+};
+
 #endif  // BASE_TASK_H__