Move metafile printing code from platform canvas to PaintCanvas

cc/paint/paint_canvas.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/paint/paint_canvas.h"
 
+#if defined(OS_MACOSX)
+namespace {
+const char kIsPreviewMetafileKey[] = "CrIsPreviewMetafile";
+}
+#endif
+
 namespace cc {
 
 PaintCanvasPassThrough::PaintCanvasPassThrough(SkCanvas* canvas)
     : SkNWayCanvas(canvas->getBaseLayerSize().width(),
                    canvas->getBaseLayerSize().height()) {
   SkIRect raster_bounds;
   canvas->getDeviceClipBounds(&raster_bounds);
   clipRect(SkRect::MakeFromIRect(raster_bounds));
   setMatrix(canvas->getTotalMatrix());
   addCanvas(canvas);
@@ skipping 14 matching lines @@
   void* pixels = canvas->accessTopLayerPixels(&info, &row_bytes);
   if (!pixels) {
     output->reset();
     return false;
   }
 
   output->reset(info, pixels, row_bytes);
   return true;
 }
 
+#if defined(OS_MACOSX)
+void SetIsPreviewMetafile(PaintCanvas* canvas, bool is_preview) {
+  SkMetaData& meta = canvas->getMetaData();
+  meta.setBool(kIsPreviewMetafileKey, is_preview);
+}
+
+bool IsPreviewMetafile(PaintCanvas* canvas) {
+  bool value;
+  SkMetaData& meta = canvas->getMetaData();
+  if (!meta.findBool(kIsPreviewMetafileKey, &value))
+    value = false;
+  return value;
+}
+#endif
+
 }  // namespace cc