Don't require getLength on Mac.

src/ports/SkImageDecoder_CG.cpp

 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCGUtils.h"
 #include "SkColorPriv.h"
 #include "SkImageDecoder.h"
 #include "SkImageEncoder.h"
 #include "SkMovie.h"
 #include "SkStream.h"
+#include "SkStreamHelpers.h"
 #include "SkTemplates.h"
 #include "SkUnPreMultiply.h"
 
 #ifdef SK_BUILD_FOR_MAC
 #include <ApplicationServices/ApplicationServices.h>
 #endif
 
 #ifdef SK_BUILD_FOR_IOS
 #include <CoreGraphics/CoreGraphics.h>
 #include <ImageIO/ImageIO.h>
 #include <MobileCoreServices/MobileCoreServices.h>
 #endif
 
 static void malloc_release_proc(void* info, const void* data, size_t size) {
     sk_free(info);
 }
 
 static CGDataProviderRef SkStreamToDataProvider(SkStream* stream) {
     // TODO: use callbacks, so we don't have to load all the data into RAM
-    size_t len = stream->getLength();
-    void* data = sk_malloc_throw(len);
-    stream->read(data, len);
+    SkAutoMalloc storage;
+    const size_t len = CopyStreamToStorage(&storage, stream);
+    void* data = storage.detach();
 
     return CGDataProviderCreateWithData(data, data, len, malloc_release_proc);
 }
 
 static CGImageSourceRef SkStreamToCGImageSource(SkStream* stream) {
     CGDataProviderRef data = SkStreamToDataProvider(stream);
     CGImageSourceRef imageSrc = CGImageSourceCreateWithDataProvider(data, 0);
     CGDataProviderRelease(data);
     return imageSrc;
 }
@@ skipping 249 matching lines @@
 
     SkAutoTCallVProc<const void, CFRelease> arsrc(imageSrc);
     const CFStringRef name = CGImageSourceGetType(imageSrc);
     if (NULL == name) {
         return SkImageDecoder::kUnknown_Format;
     }
     return UTType_to_Format(name);
 }
 
 static SkTRegistry<SkImageDecoder::Format, SkStream*> gFormatReg(get_format_cg);