Give AwakableList's wake-up method the old state in addition to the new state.

mojo/edk/system/simple_dispatcher.cc

Index: mojo/edk/system/simple_dispatcher.cc
diff --git a/mojo/edk/system/simple_dispatcher.cc b/mojo/edk/system/simple_dispatcher.cc
index c3dcd61ebce923009cbaceb2ce1af6449f13ce4a..7624b40f6c62ac1ec568fef29232d19d5eaffbdb 100644
--- a/mojo/edk/system/simple_dispatcher.cc
+++ b/mojo/edk/system/simple_dispatcher.cc
@@ -9,15 +9,15 @@
 namespace mojo {
 namespace system {
 
-SimpleDispatcher::SimpleDispatcher() {
-}
+SimpleDispatcher::SimpleDispatcher() {}
 
-SimpleDispatcher::~SimpleDispatcher() {
-}
+SimpleDispatcher::~SimpleDispatcher() {}
 
-void SimpleDispatcher::HandleSignalsStateChangedNoLock() {
+void SimpleDispatcher::OnHandleSignalsStateChangeNoLock(
+    const HandleSignalsState& old_state,
+    const HandleSignalsState& new_state) {
   mutex().AssertHeld();
-  awakable_list_.AwakeForStateChange(GetHandleSignalsStateImplNoLock());
+  awakable_list_.OnStateChange(old_state, new_state);
 }
 
 void SimpleDispatcher::CancelAllStateNoLock() {