Remove Default Touch Radii in EventGenerator

EventGenerator creates touch events in two different manners. Those that use TestTouchEvent set touch radii without exposing this to unit test classes. Chrome's gesture recognizer uses these radii when determining touch rects. This can lead to different views being targetting within unittests.

Remove the setting of these radii. Tests that wish to use larger can still create TouchEvents and call EventGenerator::Dispatch.

Review URL: https://codereview.chromium.org/522453002

Cr-Commit-Position: refs/heads/master@{#292933}

ui/events/test/event_generator.cc

@@ -47,7 +47,7 @@ class TestTouchEvent : public ui::TouchEvent {
                  int flags,
                  base::TimeDelta timestamp)
       : TouchEvent(type, root_location, flags, touch_id, timestamp,
-                   1.0f, 1.0f, 1.0f, 1.0f) {
+                   1.0f, 1.0f, 0.0f, 0.0f) {
   }
 
  private: