Fix full draw power usage increase issue

Full draw will be happened on HWUI under 90/120Hz device,there are
more draw commands under renderFrameImpl than in the 60Hz fps device,
frame.bufferAge() > (int)mSwapHistory.size() resulting in an increase
in power usage.

So need to increase (int)mSwapHistory.size() to 8, set mSwapHistory
add to 7.

Bug: 209371516
Test: Manual

Change-Id: Ic6f21e7b9dc5e7c8f36d03c57b01fa7210cff86f
Merged-In: Ic6f21e7b9dc5e7c8f36d03c57b01fa7210cff86f

libs/hwui/renderthread/CanvasContext.h

@@ -287,7 +287,7 @@ private:
     };
 
     // Need at least 4 because we do quad buffer. Add a 5th for good measure.
-    RingBuffer<SwapHistory, 5> mSwapHistory;
+    RingBuffer<SwapHistory, 7> mSwapHistory;
     int64_t mFrameNumber = -1;
     int64_t mDamageId = 0;