SF: Populate allowGroupSwitching from DM

Currently we use allowGroupSwitching only for testing. This CL
populates its value from DisplayManager so we can use user
setting to change its value.

Bug: 161776333
Test: atest libsurfaceflinger_unittest
Change-Id: I851eaee7f86083d97204cf3553e728350c942dfe
diff --git a/services/surfaceflinger/tests/LayerTransactionTest.h b/services/surfaceflinger/tests/LayerTransactionTest.h
index d4e952a..5fe2e40 100644
--- a/services/surfaceflinger/tests/LayerTransactionTest.h
+++ b/services/surfaceflinger/tests/LayerTransactionTest.h
@@ -16,6 +16,10 @@
 
 #pragma once
 
+// TODO(b/129481165): remove the #pragma below and fix conversion issues
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wconversion"
+
 #include <gtest/gtest.h>
 #include <gui/ISurfaceComposer.h>
 #include <gui/SurfaceComposerClient.h>
@@ -299,3 +303,6 @@
 };
 
 } // namespace android
+
+// TODO(b/129481165): remove the #pragma below and fix conversion issues
+#pragma clang diagnostic pop // ignored "-Wconversion"
\ No newline at end of file