aura: Introduce EventInjector.

ui/aura/BUILD.gn

Index: ui/aura/BUILD.gn
diff --git a/ui/aura/BUILD.gn b/ui/aura/BUILD.gn
index f0d256ae60b4f91c2ed42432a8346692d61757db..1fa276613bf64344af691d51e168b41abfd0d7c8 100644
--- a/ui/aura/BUILD.gn
+++ b/ui/aura/BUILD.gn
@@ -62,6 +62,8 @@ component("aura") {
     "env_input_state_controller.cc",
     "env_input_state_controller.h",
     "env_observer.h",
+    "event_injector.cc",

[sky, 2017/05/12 12:11:51]

Should EventInjector be test only? At least for mus you would need to make sure
you added the right capability, and we wouldn't want most clients using this
api.

[sadrul, 2017/05/12 21:26:08]

It unfortunately can't be, right now, because telemetry tests run with normal
chrome binary. So yes, we need to add 'test' to the manifest too :-/ Not sure if
there's some way to add such capabilities at runtime instead of in the manifest.

+    "event_injector.h",
     "input_state_lookup.cc",
     "input_state_lookup.h",
     "input_state_lookup_win.cc",