helper to convert CGImage -> SkImage

BUG=skia:

Change-Id: I07e0b8fe510d34ab541de7572cb6775478527624
Reviewed-on: https://skia-review.googlesource.com/6386
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
diff --git a/tools/Resources.h b/tools/Resources.h
index 8115fbb..fa1ca45 100644
--- a/tools/Resources.h
+++ b/tools/Resources.h
@@ -12,6 +12,7 @@
 #include "SkString.h"
 
 class SkBitmap;
+class SkData;
 class SkImage;
 class SkStreamAsset;
 class SkTypeface;
@@ -22,6 +23,7 @@
 bool GetResourceAsBitmap(const char* resource, SkBitmap* dst);
 sk_sp<SkImage> GetResourceAsImage(const char* resource);
 SkStreamAsset* GetResourceAsStream(const char* resource);
+sk_sp<SkData> GetResourceAsData(const char* resource);
 sk_sp<SkTypeface> MakeResourceAsTypeface(const char* resource);
 
 #endif  // Resources_DEFINED