Make it easier to test changes to a .icon file.

ui/gfx/paint_vector_icon.h

Index: ui/gfx/paint_vector_icon.h
diff --git a/ui/gfx/paint_vector_icon.h b/ui/gfx/paint_vector_icon.h
index 563d7cb2d3e2699f9224ccf0bdf12db0dcfa1dbf..51b244029824ae4a579d4553a48fd1ab06ab476e 100644
--- a/ui/gfx/paint_vector_icon.h
+++ b/ui/gfx/paint_vector_icon.h
@@ -28,6 +28,15 @@ GFX_EXPORT ImageSkia CreateVectorIcon(VectorIconId id,
                                       size_t dip_size,
                                       SkColor color);
 
+#if defined(GFX_VECTOR_ICONS_UNSAFE) || defined(GFX_IMPLEMENTATION)
+// Takes a string of the format expected of .icon files and renders onto
+// a canvas. This should only be used as a debugging aid and should never be
+// used in production code.
+GFX_EXPORT ImageSkia CreateVectorIconFromSource(const std::string& source,
+                                                size_t dip_size,
+                                                SkColor color);
+#endif
+
 }  // namespace gfx
 
 #endif  // UI_GFX_PAINT_VECTOR_ICON_H_