Revert "Change call-sites now that SkCanvas is not ref-counted"

ui/compositor/paint_recorder.cc

Index: ui/compositor/paint_recorder.cc
diff --git a/ui/compositor/paint_recorder.cc b/ui/compositor/paint_recorder.cc
index b48717dc307aa371a6b5887429f63700ce4d47e7..2c01e5c43d9c9f41835f99f91c3e8ea54b876a58 100644
--- a/ui/compositor/paint_recorder.cc
+++ b/ui/compositor/paint_recorder.cc
@@ -14,15 +14,15 @@
 
 namespace ui {
 
-// This class records a reference to the context, the canvas returned
-// by its recorder_, and the cache. Thus all 3 of these must remain
-// valid for the lifetime of this object.
 PaintRecorder::PaintRecorder(const PaintContext& context,
                              const gfx::Size& recording_size,
                              PaintCache* cache)
     : context_(context),
-      canvas_(context.recorder_->beginRecording(
-                  gfx::RectToSkRect(gfx::Rect(recording_size))),
+      // The SkCanvas reference returned by beginRecording is shared with
+      // the recorder_ so no need to store a RefPtr to it on this class, we just
+      // store the gfx::Canvas.
+      canvas_(sk_ref_sp(context.recorder_->beginRecording(
+                        gfx::RectToSkRect(gfx::Rect(recording_size)))),
               context.device_scale_factor_),
       cache_(cache),
       bounds_in_layer_(context.ToLayerSpaceBounds(recording_size)) {