guard references to SkColorTable

Bug: skia:6828
Change-Id: I0c8c78e70b118f51cb59dc45675e4ddcd4776108
Reviewed-on: https://skia-review.googlesource.com/24260
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
diff --git a/tools/debugger/SkDrawCommand.h b/tools/debugger/SkDrawCommand.h
index 1b3d9ab..654cbdd 100644
--- a/tools/debugger/SkDrawCommand.h
+++ b/tools/debugger/SkDrawCommand.h
@@ -10,6 +10,7 @@
 
 #include "SkBitmap.h"
 #include "SkCanvas.h"
+#include "SkFlattenable.h"
 #include "SkTLazy.h"
 #include "SkPath.h"
 #include "SkRegion.h"