ash : introduce second SessionStateController implementation.

ash/ash_switches.cc

Index: ash/ash_switches.cc
diff --git a/ash/ash_switches.cc b/ash/ash_switches.cc
index 89f6ef0685168864c18c6f506ef0df52b85ce4d7..7ae43636ea42301e46a3483e97da3adc8693ddd1 100644
--- a/ash/ash_switches.cc
+++ b/ash/ash_switches.cc
@@ -37,6 +37,9 @@ const char kAshEnableTrayDragging[] = "ash-enable-tray-dragging";
 // Enables creating a launcher per display.
 const char kAshLauncherPerDisplay[] = "ash-launcher-per-display";
 
+// If present new lock animations are enabled.
+const char kAshNewLockAnimationsEnabled[] = "ash-new-lock-animations-enabled";
+
 // Specifies the layout mode and offsets for the secondary display for
 // testing. The format is "<t|r|b|l>,<offset>" where t=TOP, r=RIGHT,
 // b=BOTTOM and L=LEFT. For example, 'r,-100' means the secondary display