hwc2: Add support for Secure Display

- Support handling secure display in HWC
- Issue NULL commit on primary display when secure display session
  starts and ends.

Change-Id: I95a8caaf1366c1d9384843d382244e1555dd6ad2

sdm/libs/hwc2/hwc_display.cpp

@@ -462,6 +462,7 @@ void HWCDisplay::BuildLayerStack() {
   display_rect_ = LayerRect();
   metadata_refresh_rate_ = 0;
   auto working_primaries = ColorPrimaries_BT709_5;
+  bool secure_display_active = false;
 
   // Add one layer for fb target
   // TODO(user): Add blit target layers
@@ -520,6 +521,10 @@ void HWCDisplay::BuildLayerStack() {
       layer_stack_.flags.skip_present = true;
     }
 
+    if (layer->input_buffer.flags.secure_display) {
+      secure_display_active = true;
+    }
+
     if (hwc_layer->GetClientRequestedCompositionType() == HWC2::Composition::Cursor) {
       // Currently we support only one HWCursor & only at top most z-order
       if ((*layer_set_.rbegin())->GetId() == hwc_layer->GetId()) {
@@ -599,6 +604,8 @@ void HWCDisplay::BuildLayerStack() {
     // Must fall back to client composition
     MarkLayersForClientComposition();
   }
+  // set secure display
+  SetSecureDisplay(secure_display_active);
 }
 
 void HWCDisplay::BuildSolidFillStack() {
@@ -1844,7 +1851,12 @@ int HWCDisplay::GetVisibleDisplayRect(hwc_rect_t *visible_rect) {
 }
 
 void HWCDisplay::SetSecureDisplay(bool secure_display_active) {
+  if (secure_display_active_ != secure_display_active) {
+    DLOGI("SecureDisplay state changed from %d to %d Needs Flush!!", secure_display_active_,
+          secure_display_active);
     secure_display_active_ = secure_display_active;
+    skip_prepare_ = true;
+  }
   return;
 }