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
Merged-In: I04daedcb9a890083cc710bab30b295e14b9872ae
Change-Id: I04daedcb9a890083cc710bab30b295e14b9872ae
diff --git a/libs/gui/tests/Surface_test.cpp b/libs/gui/tests/Surface_test.cpp
index 04686e5..2b4c901 100644
--- a/libs/gui/tests/Surface_test.cpp
+++ b/libs/gui/tests/Surface_test.cpp
@@ -625,7 +625,7 @@
         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;
     }