Delete dead SkImageDecoder::buildTileIndex and decodeSubset code

src/ports/SkImageDecoder_empty.cpp

Index: src/ports/SkImageDecoder_empty.cpp
diff --git a/src/ports/SkImageDecoder_empty.cpp b/src/ports/SkImageDecoder_empty.cpp
index 17cd685ec41de2b304cc1a044e64359edf0602af..851e23d0ca33e6c1ffb65855b2413f406d085ada 100644
--- a/src/ports/SkImageDecoder_empty.cpp
+++ b/src/ports/SkImageDecoder_empty.cpp
@@ -43,21 +43,6 @@ bool SkImageDecoder::DecodeMemory(const void*, size_t, SkBitmap*, SkColorType, M
     return false;
 }
 
-bool SkImageDecoder::buildTileIndex(SkStreamRewindable*, int *width, int *height) {
-    return false;
-}
-
-bool SkImageDecoder::onBuildTileIndex(SkStreamRewindable* stream,
-                                      int* /*width*/, int* /*height*/) {
-    delete stream;
-    return false;
-}
-
-
-bool SkImageDecoder::decodeSubset(SkBitmap*, const SkIRect&, SkColorType) {
-    return false;
-}
-
 SkImageDecoder::Format SkImageDecoder::getFormat() const {
     return kUnknown_Format;
 }
@@ -80,11 +65,6 @@ SkBitmap::Allocator* SkImageDecoder::setAllocator(SkBitmap::Allocator*) {
 
 void SkImageDecoder::setSampleSize(int) {}
 
-bool SkImageDecoder::cropBitmap(SkBitmap*, SkBitmap*, int, int, int, int, int,
-                    int, int) {
-    return false;
-}
-
 bool SkImageDecoder::allocPixelRef(SkBitmap*, SkColorTable*) const {
     return false;
 }