add runtime option to provide data->imagegenerator factory

BUG=skia:

Review URL: https://codereview.chromium.org/1229933003

2 files changed, 16 insertions, 1 deletions

diff --git a/include/core/SkGraphics.h b/include/core/SkGraphics.h
index ea74c586d2..e552633d5f 100644
--- a/include/core/SkGraphics.h
+++ b/include/core/SkGraphics.h
@@ -10,6 +10,9 @@
 
 #include "SkTypes.h"
 
+class SkData;
+class SkImageGenerator;
+
 class SK_API SkGraphics {
 public:
     /**
@@ -140,6 +143,16 @@ public:
      *  global font cache.
      */
     static void SetTLSFontCacheLimit(size_t bytes);
+
+    typedef SkImageGenerator* (*ImageGeneratorFromEncodedFactory)(SkData*);
+
+    /**
+     *  To instantiate images from encoded data, first looks at this runtime function-ptr. If it
+     *  exists, it is called to create an SkImageGenerator from SkData. If there is no function-ptr
+     *  or there is, but it returns NULL, then skia will call its internal default implementation.
+     */
+    static ImageGeneratorFromEncodedFactory GetImageGeneratorFromEncodedFactory();
+    static void SetImageGeneratorFromEncodedFactory(ImageGeneratorFromEncodedFactory);
 };
 
 class SkAutoGraphics {
diff --git a/include/core/SkImageGenerator.h b/include/core/SkImageGenerator.h
index a398697e6b..46001c8537 100644
--- a/include/core/SkImageGenerator.h
+++ b/include/core/SkImageGenerator.h
@@ -199,7 +199,7 @@ public:
      *  this returns a new ImageGenerator for it. Otherwise this returns NULL. Either way
      *  the caller is still responsible for managing their ownership of the data.
      */
-    static SkImageGenerator* NewFromData(SkData*);
+    static SkImageGenerator* NewFromEncoded(SkData*);
 
 protected:
     SkImageGenerator(const SkImageInfo& info) : fInfo(info) {}
@@ -220,6 +220,8 @@ protected:
 
 private:
     const SkImageInfo fInfo;
+
+    static SkImageGenerator* NewFromEncodedImpl(SkData*);
 };
 
 #endif  // SkImageGenerator_DEFINED