now able to set the layer stack on a DisplayDevice

Change-Id: Ia9691cf221b9444c243eb468d9e276a30e600b6b
diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index 56ac635..326a124 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -313,6 +313,13 @@
 
 // ----------------------------------------------------------------------------
 
+void DisplayDevice::setLayerStack(uint32_t stack) {
+    mLayerStack = stack;
+    dirtyRegion.set(bounds());
+}
+
+// ----------------------------------------------------------------------------
+
 status_t DisplayDevice::orientationToTransfrom(
         int orientation, int w, int h, Transform* tr)
 {
diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index 78d44f3..7efd3bc 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -91,6 +91,8 @@
     bool                    getSecureLayerVisible() const;
 
     status_t                setOrientation(int orientation);
+    void                    setLayerStack(uint32_t stack);
+
     int                     getOrientation() const { return mOrientation; }
     const Transform&        getTransform() const { return mGlobalTransform; }
     uint32_t                getLayerStack() const { return mLayerStack; }
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 1f9d694..1c15c82 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -857,7 +857,7 @@
                     const DisplayDeviceState& state(curr[i]);
                     if (state.layerStack != draw[i].layerStack) {
                         const sp<DisplayDevice>& disp(getDisplayDevice(state.id));
-                        //disp->setLayerStack(state.layerStack); // FIXME: set layer stack
+                        disp->setLayerStack(state.layerStack);
                     }
                     if (curr[i].orientation != draw[i].orientation) {
                         const sp<DisplayDevice>& disp(getDisplayDevice(state.id));