Use SwapBuffersWithBounds on Chromecast

1) Compute bounds of non-transparent content in Cast overlay
strategy.
2) Pass these bounds through via swap call (SwapBuffersWithBounds)

BUG=687690
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2693023002
Cr-Commit-Position: refs/heads/master@{#453424}

diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 4ca2f28..e0d8f256 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn

@@ -216,6 +216,8 @@
     "output/overlay_strategy_single_on_top.h",
     "output/overlay_strategy_underlay.cc",
     "output/overlay_strategy_underlay.h",
+    "output/overlay_strategy_underlay_cast.cc",
+    "output/overlay_strategy_underlay_cast.h",
     "output/program_binding.cc",
     "output/program_binding.h",
     "output/render_surface_filters.cc",