Make DocumentMarkerController::AddMarker() take a pointer instead of a const ref

Right now this method can take a const reference despite DMC possibly later
needing to edit the marker because the current implementation always copies the
marker (to construct a RenderedDocumentMarker). However, this is not guaranteed
by the API, and will be changed in the future once we no longer construct
RenderedDocumentMarkers for all MarkerTypes. So this method needs to be changed
to take a non-const pointer (could use a ref but I think doing so is discouraged
by the style guide). Also, the methods that call AddMarker() need to pass
pointers to heap-allocated objects.

BUG=707867

Review-Url: https://codereview.chromium.org/2833043002
Cr-Commit-Position: refs/heads/master@{#466596}
2 files changed