SF: Add test for FrameStats refresh rate

Adds a Transaction_test to ensure that the refresh rate field of
FrameStats is properly initialized. This is also caught by CTS, but
adding the test here should avoid a long round-trip time.

Bug: 111854867
Test: Manual, test catches regression fixed by ag/4663082
Change-Id: I4db5fba6a05dbcd5d8566dd215756e0c49bd1053
diff --git a/services/surfaceflinger/tests/Transaction_test.cpp b/services/surfaceflinger/tests/Transaction_test.cpp
index bde6614..4ab4fec 100644
--- a/services/surfaceflinger/tests/Transaction_test.cpp
+++ b/services/surfaceflinger/tests/Transaction_test.cpp
@@ -1422,6 +1422,19 @@
     }
 }
 
+TEST_P(LayerTypeTransactionTest, RefreshRateIsInitialized) {
+    sp<SurfaceControl> layer;
+    ASSERT_NO_FATAL_FAILURE(layer = createLayer("test", 32, 32));
+
+    sp<IBinder> handle = layer->getHandle();
+    ASSERT_TRUE(handle != nullptr);
+
+    FrameStats frameStats;
+    mClient->getLayerFrameStats(handle, &frameStats);
+
+    ASSERT_GT(frameStats.refreshPeriodNano, static_cast<nsecs_t>(0));
+}
+
 TEST_F(LayerTransactionTest, SetCropBasic_BufferQueue) {
     sp<SurfaceControl> layer;
     ASSERT_NO_FATAL_FAILURE(layer = createLayer("test", 32, 32));