SurfaceFlinger: add debug information when vsync is not generated

Print debug information about VsyncReactor internal state when
we expect a vsync event but it is not generated.

Bug: 151892277
Test: adb shell dumpsys SurfaceFlinger --dispsync
Test: simulate a missed vsync and observed logcat
Change-Id: Ia98cb884321d0c25610c4d721f422d9cd05c8c5e
diff --git a/services/surfaceflinger/tests/unittests/EventThreadTest.cpp b/services/surfaceflinger/tests/unittests/EventThreadTest.cpp
index 65b3e35..ba5c0c2 100644
--- a/services/surfaceflinger/tests/unittests/EventThreadTest.cpp
+++ b/services/surfaceflinger/tests/unittests/EventThreadTest.cpp
@@ -48,6 +48,7 @@
     MOCK_METHOD1(setCallback, void(VSyncSource::Callback*));
     MOCK_METHOD1(setPhaseOffset, void(nsecs_t));
     MOCK_METHOD1(pauseVsyncCallback, void(bool));
+    MOCK_CONST_METHOD1(dump, void(std::string&));
 };
 
 } // namespace
diff --git a/services/surfaceflinger/tests/unittests/VSyncDispatchRealtimeTest.cpp b/services/surfaceflinger/tests/unittests/VSyncDispatchRealtimeTest.cpp
index caac61d..be49ef3 100644
--- a/services/surfaceflinger/tests/unittests/VSyncDispatchRealtimeTest.cpp
+++ b/services/surfaceflinger/tests/unittests/VSyncDispatchRealtimeTest.cpp
@@ -51,6 +51,7 @@
 
     void setPeriod(nsecs_t) final {}
     void resetModel() final {}
+    void dump(std::string&) const final {}
 
 private:
     nsecs_t const mPeriod;
@@ -85,6 +86,7 @@
 
     void setPeriod(nsecs_t) final {}
     void resetModel() final {}
+    void dump(std::string&) const final {}
 
 private:
     std::mutex mutable mMutex;
diff --git a/services/surfaceflinger/tests/unittests/VSyncDispatchTimerQueueTest.cpp b/services/surfaceflinger/tests/unittests/VSyncDispatchTimerQueueTest.cpp
index 3ab38e4..3543361 100644
--- a/services/surfaceflinger/tests/unittests/VSyncDispatchTimerQueueTest.cpp
+++ b/services/surfaceflinger/tests/unittests/VSyncDispatchTimerQueueTest.cpp
@@ -47,6 +47,7 @@
     MOCK_CONST_METHOD0(currentPeriod, nsecs_t());
     MOCK_METHOD1(setPeriod, void(nsecs_t));
     MOCK_METHOD0(resetModel, void());
+    MOCK_CONST_METHOD1(dump, void(std::string&));
 
     nsecs_t nextVSyncTime(nsecs_t timePoint) const {
         if (timePoint % mPeriod == 0) {
diff --git a/services/surfaceflinger/tests/unittests/VSyncReactorTest.cpp b/services/surfaceflinger/tests/unittests/VSyncReactorTest.cpp
index ac95938..4f150ef 100644
--- a/services/surfaceflinger/tests/unittests/VSyncReactorTest.cpp
+++ b/services/surfaceflinger/tests/unittests/VSyncReactorTest.cpp
@@ -41,6 +41,7 @@
     MOCK_CONST_METHOD0(currentPeriod, nsecs_t());
     MOCK_METHOD1(setPeriod, void(nsecs_t));
     MOCK_METHOD0(resetModel, void());
+    MOCK_CONST_METHOD1(dump, void(std::string&));
 };
 
 class VSyncTrackerWrapper : public VSyncTracker {
@@ -56,6 +57,7 @@
     nsecs_t currentPeriod() const final { return mTracker->currentPeriod(); }
     void setPeriod(nsecs_t period) final { mTracker->setPeriod(period); }
     void resetModel() final { mTracker->resetModel(); }
+    void dump(std::string& result) const final { mTracker->dump(result); }
 
 private:
     std::shared_ptr<VSyncTracker> const mTracker;
@@ -83,6 +85,7 @@
     MOCK_METHOD1(unregisterCallback, void(CallbackToken));
     MOCK_METHOD3(schedule, ScheduleResult(CallbackToken, nsecs_t, nsecs_t));
     MOCK_METHOD1(cancel, CancelResult(CallbackToken token));
+    MOCK_CONST_METHOD1(dump, void(std::string&));
 };
 
 class VSyncDispatchWrapper : public VSyncDispatch {
@@ -102,6 +105,8 @@
 
     CancelResult cancel(CallbackToken token) final { return mDispatch->cancel(token); }
 
+    void dump(std::string& result) const final { return mDispatch->dump(result); }
+
 private:
     std::shared_ptr<VSyncDispatch> const mDispatch;
 };