Add plumbing for text only fiddles.

BUG=skia:

Change-Id: If3967f868c482bbded7185a0ed7c6559cd2858c5
Reviewed-on: https://skia-review.googlesource.com/8334
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Joe Gregorio <jcgregorio@google.com>
diff --git a/tools/fiddle/fiddle_main.h b/tools/fiddle/fiddle_main.h
index a03eebc..078c26c 100644
--- a/tools/fiddle/fiddle_main.h
+++ b/tools/fiddle/fiddle_main.h
@@ -24,7 +24,7 @@
 extern sk_sp<SkImage> image;
 
 struct DrawOptions {
-    DrawOptions(int w, int h, bool r, bool g, bool p, bool k, bool srgb, bool f16, const char* s)
+    DrawOptions(int w, int h, bool r, bool g, bool p, bool k, bool srgb, bool f16, bool textOnly, const char* s)
         : size(SkISize::Make(w, h))
         , raster(r)
         , gpu(g)
@@ -32,6 +32,7 @@
         , skp(k)
         , srgb(srgb)
         , f16(f16)
+        , textOnly(textOnly)
         , source(s)
     {
         // F16 mode is only valid for color correct backends.
@@ -44,10 +45,12 @@
     bool skp;
     bool srgb;
     bool f16;
+    bool textOnly;
     const char* source;
 };
 
 extern DrawOptions GetDrawOptions();
+extern void SkDebugf(const char * format, ...);
 extern void draw(SkCanvas*);
 
 #endif  // fiddle_main_DEFINED