SurfaceFlinger: add composer 2.4 vsync api to DisplayHardware

Add the new functions to DisplayHardware wrappers. The following CLs
will do something useful with the new functionality.

Test: rev up composer to 2.4 and test refresh rate switching
Bug: 141329414
Change-Id: Iaf98d0abc56dd393845b16c87dd92b0bad582c0f
diff --git a/services/surfaceflinger/tests/unittests/DisplayTransactionTest.cpp b/services/surfaceflinger/tests/unittests/DisplayTransactionTest.cpp
index b1a4951..db7d04c 100644
--- a/services/surfaceflinger/tests/unittests/DisplayTransactionTest.cpp
+++ b/services/surfaceflinger/tests/unittests/DisplayTransactionTest.cpp
@@ -469,6 +469,10 @@
                     getDisplayAttribute(HWC_DISPLAY_ID, HWC_ACTIVE_CONFIG_ID,
                                         IComposerClient::Attribute::DPI_Y, _))
                 .WillOnce(DoAll(SetArgPointee<3>(DEFAULT_DPI), Return(Error::NONE)));
+        EXPECT_CALL(*test->mComposer,
+                    getDisplayAttribute(HWC_DISPLAY_ID, HWC_ACTIVE_CONFIG_ID,
+                                        IComposerClient::Attribute::CONFIG_GROUP, _))
+                .WillOnce(DoAll(SetArgPointee<3>(-1), Return(Error::NONE)));
 
         if (PhysicalDisplay::HAS_IDENTIFICATION_DATA) {
             EXPECT_CALL(*test->mComposer, getDisplayIdentificationData(HWC_DISPLAY_ID, _, _))