initial preroll api

BUG=skia:

Review URL: https://codereview.chromium.org/855473002
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index 13b84e7..5b37e08 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -482,9 +482,9 @@
     typedef SkBitmapDevice INHERITED;
 };
 
-SkCanvas::SkCanvas(int width, int height)
+SkCanvas::SkCanvas(int width, int height, const SkSurfaceProps* props)
     : fMCStack(sizeof(MCRec), fMCRecStorage, sizeof(fMCRecStorage))
-    , fProps(SkSurfaceProps::kLegacyFontHost_InitType)
+    , fProps(SkSurfacePropsCopyOrDefault(props))
 {
     inc_canvas();