Add unit tests for FrameMetricsReporter

Test: adb shell /data/nativetest/hwui_unit_tests/hwui_unit_tests --gtest_filter="FrameMetricsReporter.*"
Change-Id: I97533bf71172cab29784d4177e53de50f285b991
diff --git a/libs/hwui/Android.bp b/libs/hwui/Android.bp
index 8d0fcd5..b931d03 100644
--- a/libs/hwui/Android.bp
+++ b/libs/hwui/Android.bp
@@ -692,6 +692,7 @@
         "tests/unit/FatVectorTests.cpp",
         "tests/unit/GraphicsStatsServiceTests.cpp",
         "tests/unit/JankTrackerTests.cpp",
+        "tests/unit/FrameMetricsReporterTests.cpp",
         "tests/unit/LayerUpdateQueueTests.cpp",
         "tests/unit/LinearAllocatorTests.cpp",
         "tests/unit/MatrixTests.cpp",