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

blimp/engine/browser_tests/input_browsertest.cc

Index: blimp/engine/browser_tests/input_browsertest.cc
diff --git a/blimp/engine/browser_tests/input_browsertest.cc b/blimp/engine/browser_tests/input_browsertest.cc
index 5f5fe6d79996ac129d080f188401863644354780..94a7f0f9d04ef61106501133df532e543577eae3 100644
--- a/blimp/engine/browser_tests/input_browsertest.cc
+++ b/blimp/engine/browser_tests/input_browsertest.cc
@@ -120,8 +120,9 @@ class InputBrowserTest : public BlimpBrowserTest {
 IN_PROC_BROWSER_TEST_F(InputBrowserTest, InputText) {
   LoadPage(kInputPagePath);
 
-  blink::WebGestureEvent event;
-  event.type = blink::WebInputEvent::Type::GestureTap;
+  blink::WebGestureEvent event(blink::WebInputEvent::Type::GestureTap,
+                               blink::WebInputEvent::NoModifiers,
+                               blink::WebInputEvent::TimeStampForTesting);
   client::ImeFeature::WebInputRequest request;
 
   // Send a tap event from the client and expect the IME dialog to show.
@@ -149,8 +150,9 @@ IN_PROC_BROWSER_TEST_F(InputBrowserTest, InputText) {
 IN_PROC_BROWSER_TEST_F(InputBrowserTest, InputTextAndSubmit) {
   LoadPage(kInputPagePath);
 
-  blink::WebGestureEvent event;
-  event.type = blink::WebInputEvent::Type::GestureTap;
+  blink::WebGestureEvent event(blink::WebInputEvent::Type::GestureTap,
+                               blink::WebInputEvent::NoModifiers,
+                               blink::WebInputEvent::TimeStampForTesting);
   client::ImeFeature::WebInputRequest request;
 
   // Send a tap event from the client and expect the IME dialog to show.