Rebase non-drawing SkCanvas subclasses to SkNoDrawCanvas

R=reed@google.com,mtklein@google.com

Change-Id: I7df84587821db561e262a915afa23108a4a78834
Reviewed-on: https://skia-review.googlesource.com/5508
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
diff --git a/include/utils/SkNoDrawCanvas.h b/include/utils/SkNoDrawCanvas.h
index 0330251..e8c5d7e 100644
--- a/include/utils/SkNoDrawCanvas.h
+++ b/include/utils/SkNoDrawCanvas.h
@@ -10,6 +10,8 @@
 
 #include "SkCanvas.h"
 
+struct SkIRect;
+
 // SkNoDrawCanvas is a helper for SkCanvas subclasses which do not need to
 // actually rasterize (e.g., analysis of the draw calls).
 //
@@ -22,6 +24,9 @@
 public:
     SkNoDrawCanvas(int width, int height);
 
+    // TODO: investigate the users of this ctor.
+    SkNoDrawCanvas(const SkIRect&);
+
 protected:
     SaveLayerStrategy getSaveLayerStrategy(const SaveLayerRec& rec) override;