Mozart: Implement basic input event dispatch with hit testing.

services/ui/input_manager/BUILD.gn

Index: services/ui/input_manager/BUILD.gn
diff --git a/services/ui/input_manager/BUILD.gn b/services/ui/input_manager/BUILD.gn
index b869f3386106fde8bd8e656fe821915059e5ce12..1b2e503f5eb17bc0a7acf9c6de757226664c88ea 100644
--- a/services/ui/input_manager/BUILD.gn
+++ b/services/ui/input_manager/BUILD.gn
@@ -11,6 +11,10 @@ mojo_native_application("input_manager") {
   sources = [
     "input_associate.cc",
     "input_associate.h",
+    "input_connection_impl.cc",
+    "input_connection_impl.h",
+    "input_dispatcher_impl.cc",
+    "input_dispatcher_impl.h",
     "input_manager_app.cc",
     "input_manager_app.h",
     "main.cc",
@@ -30,5 +34,6 @@ mojo_native_application("input_manager") {
     "//mojo/services/ui/input/interfaces",
     "//mojo/services/ui/views/cpp",
     "//mojo/services/ui/views/interfaces",
+    "//mojo/ui/associates",
   ]
 }