Convert sticky keys to a chromeos::EventRewriter phase.

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index c8d5da4888a006caf6dad660bcffd02a7cb3672a..3d10a1d77c9cebc3208a9bdb65b0ee257a539285 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -901,13 +901,6 @@ void Shell::Init(const ShellInitParams& init_params) {
 
   // The order in which event filters are added is significant.
 
-#if defined(OS_CHROMEOS)
-  // The StickyKeysController also rewrites events and must be added
-  // before observers, but after the EventRewriterEventFilter.
-  sticky_keys_controller_.reset(new StickyKeysController);
-  AddPreTargetHandler(sticky_keys_controller_.get());
-#endif
-
   // wm::UserActivityDetector passes events to observers, so let them get
   // rewritten first.
   user_activity_detector_.reset(new ::wm::UserActivityDetector);
@@ -942,6 +935,10 @@ void Shell::Init(const ShellInitParams& init_params) {
     keyboard::InitializeKeyboard();
 #endif
 
+#if defined(OS_CHROMEOS)
+  sticky_keys_controller_.reset(new StickyKeysController);
+#endif
+
   lock_state_controller_.reset(new LockStateController);
   power_button_controller_.reset(new PowerButtonController(
       lock_state_controller_.get()));