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

blimp/net/input_message_converter.cc

Index: blimp/net/input_message_converter.cc
diff --git a/blimp/net/input_message_converter.cc b/blimp/net/input_message_converter.cc
index cb0ed87eb9d57d8e5862ec400d4d511b0435b0f1..198ef4a54b9e89e07ca0f1f1931228096002f1de 100644
--- a/blimp/net/input_message_converter.cc
+++ b/blimp/net/input_message_converter.cc
@@ -15,9 +15,8 @@ namespace {
 std::unique_ptr<blink::WebGestureEvent> BuildCommonWebGesture(
     const InputMessage& proto,
     blink::WebInputEvent::Type type) {
-  std::unique_ptr<blink::WebGestureEvent> event(new blink::WebGestureEvent);
-  event->type = type;
-  event->timeStampSeconds = proto.timestamp_seconds();
+  std::unique_ptr<blink::WebGestureEvent> event(new blink::WebGestureEvent(
+      type, blink::WebInputEvent::NoModifiers, proto.timestamp_seconds()));
 
   const GestureCommon& common = proto.gesture_common();
   event->x = common.x();