Remove SaveFlags from saveLayer(Alpha)

This has been hardcoded as ALL_SAVE_FLAGS for a couple releases now.

Since it's now permanent behavior, remove the last bit of plumbing
for SaveFlags on saveLayer

Test: builds & boots
Change-Id: Iec92f27199d0b4781c2293dcdcfd45a1562a1b4e
diff --git a/libs/hwui/SkiaCanvas.h b/libs/hwui/SkiaCanvas.h
index 2cb850c8..591ae5c 100644
--- a/libs/hwui/SkiaCanvas.h
+++ b/libs/hwui/SkiaCanvas.h
@@ -73,10 +73,8 @@
     virtual void restoreToCount(int saveCount) override;
     virtual void restoreUnclippedLayer(int saveCount, const SkPaint& paint) override;
 
-    virtual int saveLayer(float left, float top, float right, float bottom, const SkPaint* paint,
-                          SaveFlags::Flags flags) override;
-    virtual int saveLayerAlpha(float left, float top, float right, float bottom, int alpha,
-                               SaveFlags::Flags flags) override;
+    virtual int saveLayer(float left, float top, float right, float bottom, const SkPaint* paint) override;
+    virtual int saveLayerAlpha(float left, float top, float right, float bottom, int alpha) override;
     virtual int saveUnclippedLayer(int left, int top, int right, int bottom) override;
 
     virtual void getMatrix(SkMatrix* outMatrix) const override;