cc: Add bounds calculation for display items.

This patch adds bounds calculation for display items, which is required
in order to put these items into an r-tree.

R=enne
BUG=529938
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1345923003

Cr-Commit-Position: refs/heads/master@{#350963}

diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index b25b8dc..01f2b02 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn

@@ -290,6 +290,8 @@
     "playback/display_item.h",
     "playback/display_item_list.cc",
     "playback/display_item_list.h",
+    "playback/display_item_list_bounds_calculator.cc",
+    "playback/display_item_list_bounds_calculator.h",
     "playback/display_item_list_settings.cc",
     "playback/display_item_list_settings.h",
     "playback/display_list_raster_source.cc",