Move code to dump GrSurface as a png to helper files

src/images/SkImagesSupport.h

Index: src/images/SkImagesSupport.h
diff --git a/src/images/SkImagesSupport.h b/src/images/SkImagesSupport.h
new file mode 100644
index 0000000000000000000000000000000000000000..20c5089567b07eb5434801899852a58aca44fde7
--- /dev/null
+++ b/src/images/SkImagesSupport.h
@@ -0,0 +1,16 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkImagesSupport_DEFINED
+#define SkImagesSupport_DEFINED
+
+#if SK_SUPPORT_GPU && defined(SK_DEVELOPER)
+class GrSurface;
+bool SkSaveGrSurfacePixelsAsPNG(GrSurface* surface, const char* filename);
+#endif
+
+#endif