Add support to dump font cache texture for debug purposes

R=robertphillips@google.com, bsalomon@google.com

Author: jvanverth@google.com

Review URL: https://codereview.chromium.org/25736002

git-svn-id: http://skia.googlecode.com/svn/trunk@11579 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrTextStrike.h b/src/gpu/GrTextStrike.h
index e311f3f..35d5008 100644
--- a/src/gpu/GrTextStrike.h
+++ b/src/gpu/GrTextStrike.h
@@ -98,6 +98,10 @@
     void validate() const {}
 #endif
 
+#ifdef SK_DEVELOPER
+    void dump() const;
+#endif
+
 private:
     friend class GrFontPurgeListener;