Route touch-events for WebViewGuest directly to guest renderer.

content/renderer/browser_plugin/browser_plugin.cc

Index: content/renderer/browser_plugin/browser_plugin.cc
diff --git a/content/renderer/browser_plugin/browser_plugin.cc b/content/renderer/browser_plugin/browser_plugin.cc
index f4b24e1cb029c0954634918d1db1fc3a77fe9973..a55548bedb85827a196fd5b09b0d1eb9c642df43 100644
--- a/content/renderer/browser_plugin/browser_plugin.cc
+++ b/content/renderer/browser_plugin/browser_plugin.cc
@@ -501,6 +501,8 @@ bool BrowserPlugin::handleInputEvent(const blink::WebInputEvent& event,
   if (guest_crashed_ || !attached())
     return false;
 
+  DCHECK(!blink::WebInputEvent::isTouchEventType(event.type));
+
   if (event.type == blink::WebInputEvent::MouseWheel) {
     auto wheel_event = static_cast<const blink::WebMouseWheelEvent&>(event);
     if (wheel_event.resendingPluginId == browser_plugin_instance_id_)