ply-image: Separate image loading and displaying.

This renames ply_frame_buffer_show_file() to
ply_frame_buffer_show_image() and makes process_images()
make a separate call to load each image that it wants to
display.  No functional changes intended apart from a debug
logging message; I'm just doing this to enable more
fine-grained benchmarking and make it possible to
preemptively load the next image.

BUG=chromium-os:33971
TEST=boot animation still works on lumpy

Change-Id: I53fbe9b2a01ce54377061400829f7c77aea11f46
Reviewed-on: https://gerrit.chromium.org/gerrit/38395
Reviewed-by: Simon Que <sque@chromium.org>
Reviewed-by: St├ęphane Marchesin <marcheu@chromium.org>
Commit-Ready: Daniel Erat <derat@chromium.org>
Tested-by: Daniel Erat <derat@chromium.org>
3 files changed