Revert "Add eLayerIsDisplayDecoration flag"

Revert submission 16511727-wm_DISPLAY_DECORATION

Reason for revert: b/211835607
Reverted Changes:
I1da3199ba:Allow changing composition from DISPLAY_DECORATION...
I1fae74b36:Update documentation for DISPLAY_DECORATION
I1da03a88f:Add eLayerIsDisplayDecoration flag
I7f22dfd03:Add/plumb SurfaceControl.DISPLAY_DECORATION

Change-Id: I449e1bb74e0d197661033bf114a25ae6ec04e418
diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index cf04ec8..aafa5e4 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -1104,8 +1104,7 @@
     }
     if ((mask & layer_state_t::eLayerOpaque) || (mask & layer_state_t::eLayerHidden) ||
         (mask & layer_state_t::eLayerSecure) || (mask & layer_state_t::eLayerSkipScreenshot) ||
-        (mask & layer_state_t::eEnableBackpressure) ||
-        (mask & layer_state_t::eLayerIsDisplayDecoration)) {
+        (mask & layer_state_t::eEnableBackpressure)) {
         s->what |= layer_state_t::eFlagsChanged;
     }
     s->flags &= ~mask;
diff --git a/libs/gui/include/gui/LayerState.h b/libs/gui/include/gui/LayerState.h
index a0d3162..b01eed4 100644
--- a/libs/gui/include/gui/LayerState.h
+++ b/libs/gui/include/gui/LayerState.h
@@ -109,7 +109,6 @@
         // set. This blocks the client until all the buffers have been presented. If the buffers
         // have presentation timestamps, then we may drop buffers.
         eEnableBackpressure = 0x100, // ENABLE_BACKPRESSURE
-        eLayerIsDisplayDecoration = 0x200,  // DISPLAY_DECORATION
     };
 
     enum {