[SurfaceFlinger] Add refresh rate counts to TimeStats

This count will be exposed to lab tests as a breakdown metric for
uncovering jank.

Bug: 144526027
Test: dumpsys SurfaceFlinger --timestats -dump
Test: libsurfaceflinger_unittest
Change-Id: I921e147e96212ad6a08fa14d6e3d7a98893a8602
diff --git a/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp b/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp
index a7a4d48..45f7ed3 100644
--- a/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp
+++ b/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp
@@ -362,6 +362,21 @@
     EXPECT_THAT(result, HasSubstr(expectedResult));
 }
 
+TEST_F(TimeStatsTest, canIncreaseRefreshRateSwitches) {
+    // this stat is not in the proto so verify by checking the string dump
+    constexpr size_t REFRESH_RATE_SWITCHES = 2;
+
+    EXPECT_TRUE(inputCommand(InputCommand::ENABLE, FMT_STRING).empty());
+    for (size_t i = 0; i < REFRESH_RATE_SWITCHES; i++) {
+        ASSERT_NO_FATAL_FAILURE(mTimeStats->incrementRefreshRateSwitches());
+    }
+
+    const std::string result(inputCommand(InputCommand::DUMP_ALL, FMT_STRING));
+    const std::string expectedResult =
+            "refreshRateSwitches = " + std::to_string(REFRESH_RATE_SWITCHES);
+    EXPECT_THAT(result, HasSubstr(expectedResult));
+}
+
 TEST_F(TimeStatsTest, canAverageFrameDuration) {
     EXPECT_TRUE(inputCommand(InputCommand::ENABLE, FMT_STRING).empty());
     mTimeStats->setPowerMode(HWC_POWER_MODE_NORMAL);
@@ -744,6 +759,7 @@
     // These stats are not in the proto so verify by checking the string dump.
     EXPECT_TRUE(inputCommand(InputCommand::ENABLE, FMT_STRING).empty());
     ASSERT_NO_FATAL_FAILURE(mTimeStats->incrementClientCompositionReusedFrames());
+    ASSERT_NO_FATAL_FAILURE(mTimeStats->incrementRefreshRateSwitches());
     mTimeStats->setPowerMode(HWC_POWER_MODE_NORMAL);
     mTimeStats
             ->recordFrameDuration(std::chrono::duration_cast<std::chrono::nanoseconds>(1ms).count(),
@@ -759,6 +775,7 @@
 
     const std::string result(inputCommand(InputCommand::DUMP_ALL, FMT_STRING));
     EXPECT_THAT(result, HasSubstr("clientCompositionReusedFrames = 0"));
+    EXPECT_THAT(result, HasSubstr("refreshRateSwitches = 0"));
     EXPECT_THAT(result, HasSubstr("averageFrameDuration = 0.000 ms"));
     EXPECT_THAT(result, HasSubstr("averageRenderEngineTiming = 0.000 ms"));
 }