Implement an API for vrwm to query if the current vr app is active

The API returns if the client_order 0 layer is visible or not. This
aids in 2D app detection

Bug: None
Test: Manual with permissionsgen & calculator

Change-Id: Id988e61a9f93885e93c28ed83ffaffd84f3bdf15
diff --git a/libs/vr/libdisplay/display_client.cpp b/libs/vr/libdisplay/display_client.cpp
index 50d95f7..9952e59 100644
--- a/libs/vr/libdisplay/display_client.cpp
+++ b/libs/vr/libdisplay/display_client.cpp
@@ -265,6 +265,12 @@
   return BufferConsumer::Import(std::move(status));
 }
 
+bool DisplayClient::IsVrAppRunning() {
+  auto status = InvokeRemoteMethod<DisplayRPC::IsVrAppRunning>();
+  if (!status)
+    return 0;
+  return static_cast<bool>(status.get());
+}
 
 }  // namespace dvr
 }  // namespace android
diff --git a/libs/vr/libdisplay/include/private/dvr/display_client.h b/libs/vr/libdisplay/include/private/dvr/display_client.h
index f579a8c..378f67c 100644
--- a/libs/vr/libdisplay/include/private/dvr/display_client.h
+++ b/libs/vr/libdisplay/include/private/dvr/display_client.h
@@ -110,6 +110,9 @@
 
   std::unique_ptr<BufferConsumer> GetPoseBuffer();
 
+  // Temporary query for current VR status. Will be removed later.
+  bool IsVrAppRunning();
+
  private:
   friend BASE;
 
diff --git a/libs/vr/libdisplay/include/private/dvr/display_rpc.h b/libs/vr/libdisplay/include/private/dvr/display_rpc.h
index 7a2986a..ac08650 100644
--- a/libs/vr/libdisplay/include/private/dvr/display_rpc.h
+++ b/libs/vr/libdisplay/include/private/dvr/display_rpc.h
@@ -219,6 +219,7 @@
     kOpVideoMeshSurfaceCreateProducerQueue,
     kOpSetViewerParams,
     kOpGetPoseBuffer,
+    kOpIsVrAppRunning,
   };
 
   // Aliases.
@@ -248,6 +249,7 @@
                     void(const ViewerParams& viewer_params));
   PDX_REMOTE_METHOD(GetPoseBuffer, kOpGetPoseBuffer,
                     LocalChannelHandle(Void));
+  PDX_REMOTE_METHOD(IsVrAppRunning, kOpIsVrAppRunning, int(Void));
 };
 
 struct DisplayManagerRPC {