Add mechanism for a task's windows to be trusted overlays (SF)

- Add a layer state to indicate that this layer and its children
  in the hierarchy are trusted. This can only be set by callers
  holding ACCESS_SURFACE_FLINGER, and will be used for the PIP
  task layer to indicate that activities in PIP are trusted (as
  they are controlled only by the user and SystemUI)

Bug: 191529039
Test: TBD

Change-Id: Id92ccb087bd0d8dbaeeef3ba50b67fe015e53db8
diff --git a/services/surfaceflinger/layerproto/LayerProtoParser.cpp b/services/surfaceflinger/layerproto/LayerProtoParser.cpp
index aef670d..2841f7c 100644
--- a/services/surfaceflinger/layerproto/LayerProtoParser.cpp
+++ b/services/surfaceflinger/layerproto/LayerProtoParser.cpp
@@ -105,6 +105,7 @@
     layer.queuedFrames = layerProto.queued_frames();
     layer.refreshPending = layerProto.refresh_pending();
     layer.isProtected = layerProto.is_protected();
+    layer.isTrustedOverlay = layerProto.is_trusted_overlay();
     layer.cornerRadius = layerProto.corner_radius();
     layer.backgroundBlurRadius = layerProto.background_blur_radius();
     for (const auto& entry : layerProto.metadata()) {
@@ -289,6 +290,7 @@
     StringAppendF(&result, "crop=%s, ", crop.to_string().c_str());
     StringAppendF(&result, "cornerRadius=%f, ", cornerRadius);
     StringAppendF(&result, "isProtected=%1d, ", isProtected);
+    StringAppendF(&result, "isTrustedOverlay=%1d, ", isTrustedOverlay);
     StringAppendF(&result, "isOpaque=%1d, invalidate=%1d, ", isOpaque, invalidate);
     StringAppendF(&result, "dataspace=%s, ", dataspace.c_str());
     StringAppendF(&result, "defaultPixelFormat=%s, ", pixelFormat.c_str());
diff --git a/services/surfaceflinger/layerproto/include/layerproto/LayerProtoParser.h b/services/surfaceflinger/layerproto/include/layerproto/LayerProtoParser.h
index c48354f..52503ba 100644
--- a/services/surfaceflinger/layerproto/include/layerproto/LayerProtoParser.h
+++ b/services/surfaceflinger/layerproto/include/layerproto/LayerProtoParser.h
@@ -109,6 +109,7 @@
         int32_t queuedFrames;
         bool refreshPending;
         bool isProtected;
+        bool isTrustedOverlay;
         float cornerRadius;
         int backgroundBlurRadius;
         LayerMetadata metadata;
diff --git a/services/surfaceflinger/layerproto/layers.proto b/services/surfaceflinger/layerproto/layers.proto
index 9f25674..dddc677 100644
--- a/services/surfaceflinger/layerproto/layers.proto
+++ b/services/surfaceflinger/layerproto/layers.proto
@@ -128,6 +128,8 @@
 
   // Regions of a layer, where blur should be applied.
   repeated BlurRegion blur_regions = 54;
+
+  bool is_trusted_overlay = 55;
 }
 
 message PositionProto {