Call Layer::getLayerDebugInfo from the main thread

Fixes an issue where drawing state could be accessed from a binder
thread. The function also mixed current state with drawing state
incorrectly. The function now only retrieves drawing state.

Bug: 150226608
Test: Steps in bug doesn't repro
Test: atest sffakehwc_test
Change-Id: I5537c53e8214e2785473839d71fd483d1a3219b6
diff --git a/libs/gui/tests/Surface_test.cpp b/libs/gui/tests/Surface_test.cpp
index a1d12a5..c2b4ef9 100644
--- a/libs/gui/tests/Surface_test.cpp
+++ b/libs/gui/tests/Surface_test.cpp
@@ -785,7 +785,7 @@
         return NO_ERROR;
     }
     status_t injectVSync(nsecs_t /*when*/) override { return NO_ERROR; }
-    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* /*layers*/) const override {
+    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* /*layers*/) override {
         return NO_ERROR;
     }
     status_t getCompositionPreference(