Wires up drag/drop for aura-mus

I combined the drag and drop handling into the same class as the data
is shared in the case of drop targeting the same client that initiated
the drag.

BUG=659155
TEST=covered by tests
R=erg@chromium.org, sadrul@chromium.org, tsepez@chromium.org
TBR=sadrul@chromium.org

Review-Url: https://codereview.chromium.org/2455963006
Cr-Commit-Position: refs/heads/master@{#428515}

diff --git a/ui/aura/BUILD.gn b/ui/aura/BUILD.gn
index 7c527e9..e0af522 100644
--- a/ui/aura/BUILD.gn
+++ b/ui/aura/BUILD.gn

@@ -15,8 +15,6 @@
     "../wm/public/activation_delegate.h",
     "../wm/public/animation_host.cc",
     "../wm/public/animation_host.h",
-    "../wm/public/drag_drop_delegate.cc",
-    "../wm/public/drag_drop_delegate.h",
     "../wm/public/scoped_drag_drop_disabler.cc",
     "../wm/public/scoped_drag_drop_disabler.h",
     "../wm/public/scoped_tooltip_disabler.cc",
@@ -40,6 +38,8 @@
     "client/default_capture_client.h",
     "client/drag_drop_client.cc",
     "client/drag_drop_client.h",
+    "client/drag_drop_delegate.cc",
+    "client/drag_drop_delegate.h",
     "client/event_client.cc",
     "client/event_client.h",
     "client/focus_change_observer.cc",
@@ -68,6 +68,9 @@
     "input_state_lookup_win.h",
     "layout_manager.cc",
     "layout_manager.h",
+    "mus/drag_drop_controller_host.h",
+    "mus/drag_drop_controller_mus.cc",
+    "mus/drag_drop_controller_mus.h",
     "mus/in_flight_change.cc",
     "mus/in_flight_change.h",
     "mus/input_method_mus.cc",