[Fuchsia] Add ui.policy.Presenter in content_shell manifest

content_shell uses ui.policy.Presenter API to present UI. The API wasn't
listed in content_shell.cmx, so it was failing to connect to the
presenter.
Also added content/shell/fuchsia/OWNERS file (required by presubmit
checks for all cmx files).


Bug: 1067477
Change-Id: I477644a28549f9314e9ffd007d1da9abcc6c8b72
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2443449Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Charlie Reis <creis@chromium.org>
Commit-Queue: Charlie Reis <creis@chromium.org>
Auto-Submit: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813763}

content/shell/fuchsia/OWNERS

+file://build/fuchsia/OWNERS
+# COMPONENT: Fuchsia
+# OS: Fuchsia
+# TEAM: cr-fuchsia@chromium.org
+
+per-file *.cmx=set noparent
+per-file *.cmx=file://fuchsia/SECURITY_OWNERS

content/shell/fuchsia/content_shell.cmx

@@ -25,6 +25,7 @@
       "fuchsia.sysmem.Allocator",
       "fuchsia.ui.input.ImeService",
       "fuchsia.ui.input.ImeVisibilityService",
+      "fuchsia.ui.policy.Presenter",
       "fuchsia.ui.scenic.Scenic",
       "fuchsia.vulkan.loader.Loader"
     ]