Make frame number type consistent

The frame numbers are ultimately stored as uint64_t so to avoid any implementation dependent casting we make sure all direct and indirect references to this value are stored as uint64_t

Test: N/A
Change-Id: I080c94b1007f2e884cf0fa3583bf51badc913a05
diff --git a/libs/hwui/renderthread/CanvasContext.h b/libs/hwui/renderthread/CanvasContext.h
index b21dc75..852cbda6 100644
--- a/libs/hwui/renderthread/CanvasContext.h
+++ b/libs/hwui/renderthread/CanvasContext.h
@@ -173,7 +173,7 @@
     // Used to queue up work that needs to be completed before this frame completes
     void enqueueFrameWork(std::function<void()>&& func);
 
-    int64_t getFrameNumber();
+    uint64_t getFrameNumber();
 
     void waitOnFences();
 
@@ -281,7 +281,7 @@
 
     // Need at least 4 because we do quad buffer. Add a 5th for good measure.
     RingBuffer<SwapHistory, 5> mSwapHistory;
-    int64_t mFrameNumber = -1;
+    uint64_t mFrameNumber = -1;
     int64_t mDamageId = 0;
 
     // last vsync for a dropped frame due to stuffed queue