hwui: improve RenderThread jank classificaion

Mark UI frames that didn't make it to their expected presentation
due to RenderThread animations as dropped.

Screenshot from Perfetto: https://screenshot.googleplex.com/3pQuNaDYAhHLYu7

Bug: 210605870
Test: manual
Change-Id: I709b2bacbafb8027d97f2fcc39831de7735fc3ff
Merged-In: I709b2bacbafb8027d97f2fcc39831de7735fc3ff
diff --git a/libs/hwui/renderthread/CanvasContext.h b/libs/hwui/renderthread/CanvasContext.h
index 5219b57..32ac5af 100644
--- a/libs/hwui/renderthread/CanvasContext.h
+++ b/libs/hwui/renderthread/CanvasContext.h
@@ -366,6 +366,12 @@
 
     ColorMode mColorMode = ColorMode::Default;
     float mTargetSdrHdrRatio = 1.f;
+
+    struct SkippedFrameInfo {
+        int64_t vsyncId;
+        int64_t startTime;
+    };
+    std::optional<SkippedFrameInfo> mSkippedFrameInfo;
 };
 
 } /* namespace renderthread */