Avoid getLength in ico decoder.

src/images/SkImageDecoder_libico.cpp

Index: src/images/SkImageDecoder_libico.cpp
diff --git a/src/images/SkImageDecoder_libico.cpp b/src/images/SkImageDecoder_libico.cpp
index b14e19614ceca7c65ac4567c6983d4835c6d9844..f4e17b9643d9cbd0e26cf2457ab048c69ebcd0b2 100644
--- a/src/images/SkImageDecoder_libico.cpp
+++ b/src/images/SkImageDecoder_libico.cpp
@@ -73,15 +73,19 @@ static int calculateRowBytesFor8888(int w, int bitCount)
     return 0;
 }
 
+// Defined in SkImageDecoder.cpp
+extern size_t copy_stream_to_storage(SkAutoMalloc* storage, SkStream* stream);
+
 bool SkICOImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode)
 {
-    size_t length = stream->getLength();
-    SkAutoMalloc autoMal(length);
-    unsigned char* buf = (unsigned char*)autoMal.get();
-    if (stream->read((void*)buf, length) != length) {
+    SkAutoMalloc autoMal;
+    const size_t length = copy_stream_to_storage(&autoMal, stream);
+    if (0 == length) {
         return false;
     }
 
+    unsigned char* buf = (unsigned char*)autoMal.get();
+
     //these should always be the same - should i use for error checking? - what about files that have some
     //incorrect values, but still decode properly?
     int reserved = read2Bytes(buf, 0);    // 0