remove dead flags

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1543323002

TBR=

Review URL: https://codereview.chromium.org/1543323002

src/core/SkCanvas.cpp

@@ -2228,10 +2228,6 @@ void SkCanvas::onDrawPath(const SkPath& path, const SkPaint& paint) {
 }
 
 bool SkCanvas::canDrawBitmapAsSprite(SkScalar x, SkScalar y, int w, int h, const SkPaint& paint) {
-#ifdef SK_SUPPORT_LEGACY_LAYER_BITMAP_IMAGEFILTERS
-    return false;
-#endif
-
     if (!paint.getImageFilter()) {
         return false;
     }

src/effects/SkOffsetImageFilter.cpp

@@ -20,11 +20,7 @@ bool SkOffsetImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& source,
                                         SkIPoint* offset) const {
     SkBitmap src = source;
     SkIPoint srcOffset = SkIPoint::Make(0, 0);
-#ifdef SK_DISABLE_OFFSETIMAGEFILTER_OPTIMIZATION
-    if (false) {
-#else
     if (!cropRectIsSet()) {
-#endif
         if (!this->filterInput(0, proxy, source, ctx, &src, &srcOffset)) {
             return false;
         }