Use ui::Event instead of mojom::EventPtr in mus::InputEventHandler.

content/renderer/mus/BUILD.gn

Index: content/renderer/mus/BUILD.gn
diff --git a/content/renderer/mus/BUILD.gn b/content/renderer/mus/BUILD.gn
index 0325c9f4bb2268442804076599bd5681cc4140d8..dc471fc80ba86ed6343a8287d064cdf46b4766ee 100644
--- a/content/renderer/mus/BUILD.gn
+++ b/content/renderer/mus/BUILD.gn
@@ -24,9 +24,11 @@ source_set("mus") {
     "//mojo/common",
     "//mojo/converters/blink",
     "//mojo/converters/geometry",
+    "//mojo/converters/input_events",
     "//mojo/converters/surfaces",
     "//mojo/shell/public/cpp",
     "//third_party/WebKit/public:blink",
+    "//ui/events:events",
     "//ui/events:events_base",
   ]
 }