Add constructors to WebInputEvents and setters so we can work at cleaning up these public structs.

content/browser/renderer_host/input/mock_input_ack_handler.h

Index: content/browser/renderer_host/input/mock_input_ack_handler.h
diff --git a/content/browser/renderer_host/input/mock_input_ack_handler.h b/content/browser/renderer_host/input/mock_input_ack_handler.h
index 90310ff9888587eea435ac0b38b7029fc3be840c..cb390ae6934a46fcf71619b5273371a068d4afe2 100644
--- a/content/browser/renderer_host/input/mock_input_ack_handler.h
+++ b/content/browser/renderer_host/input/mock_input_ack_handler.h
@@ -58,7 +58,7 @@ class MockInputAckHandler : public InputAckHandler {
   blink::WebInputEvent::Type ack_event_type() const { return ack_event_type_; }
 
   const NativeWebKeyboardEvent& acked_keyboard_event() const {
-    return acked_key_event_;
+    return *acked_key_event_;
   }
   const blink::WebMouseWheelEvent& acked_wheel_event() const {
     return acked_wheel_event_;
@@ -80,7 +80,7 @@ class MockInputAckHandler : public InputAckHandler {
   bool unexpected_event_ack_called_;
   blink::WebInputEvent::Type ack_event_type_;
   InputEventAckState ack_state_;
-  NativeWebKeyboardEvent acked_key_event_;
+  std::unique_ptr<NativeWebKeyboardEvent> acked_key_event_;
   blink::WebMouseWheelEvent acked_wheel_event_;
   TouchEventWithLatencyInfo acked_touch_event_;
   blink::WebGestureEvent acked_gesture_event_;