Paint: remove readPixels.

cc/paint/skia_paint_canvas.h

Index: cc/paint/skia_paint_canvas.h
diff --git a/cc/paint/skia_paint_canvas.h b/cc/paint/skia_paint_canvas.h
index f751f7781664aed4a1e5b28d0dc419a34c44ed91..0efd2edd56447ab4af1e28b3e674d05bd6695e91 100644
--- a/cc/paint/skia_paint_canvas.h
+++ b/cc/paint/skia_paint_canvas.h
@@ -39,13 +39,6 @@ class CC_PAINT_EXPORT SkiaPaintCanvas final : public PaintCanvas {
   void flush() override;
 
   SkISize getBaseLayerSize() const override;
-  bool readPixels(const SkImageInfo& dest_info,
-                  void* dest_pixels,
-                  size_t dest_row_bytes,
-                  int src_x,
-                  int src_y) override;
-  bool readPixels(SkBitmap* bitmap, int src_x, int src_y) override;
-  bool readPixels(const SkIRect& srcRect, SkBitmap* bitmap) override;
   bool writePixels(const SkImageInfo& info,
                    const void* pixels,
                    size_t row_bytes,