remove all references to legacy Config8888

src/pdf/SkPDFDevice.cpp

Index: src/pdf/SkPDFDevice.cpp
diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index b8e681874169d6a3887ad884efa245f62a63348e..246f30ded11461366d2142d911429ad29473f52f 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -2307,13 +2307,6 @@ void SkPDFDevice::internalDrawBitmap(const SkMatrix& origMatrix,
                                 &content.entry()->fContent);
 }
 
-#ifdef SK_SUPPORT_LEGACY_READPIXELSCONFIG
-bool SkPDFDevice::onReadPixels(const SkBitmap& bitmap, int x, int y,
-                               SkCanvas::Config8888) {
-    return false;
-}
-#endif
-
 bool SkPDFDevice::allowImageFilter(const SkImageFilter*) {
     return false;
 }