touch: Make sure the correct radius values are used for touch events.

content/browser/renderer_host/web_input_event_aurax11.cc

Index: content/browser/renderer_host/web_input_event_aurax11.cc
diff --git a/content/browser/renderer_host/web_input_event_aurax11.cc b/content/browser/renderer_host/web_input_event_aurax11.cc
index 8b20ea224089fe918e87b201b063710b53474968..905a52e5dfc297ca5c1a1c566fe00b1708a3cc50 100644
--- a/content/browser/renderer_host/web_input_event_aurax11.cc
+++ b/content/browser/renderer_host/web_input_event_aurax11.cc
@@ -410,8 +410,9 @@ WebKit::WebTouchPoint* UpdateWebTouchEventFromAuraEvent(
   if (!point)
     return NULL;
 
-  point->radiusX = event->radius_x();
-  point->radiusY = event->radius_y();
+  // The spec requires the radii values to be positive (and 1 when unknown).
+  point->radiusX = std::max(1.f, event->radius_x());
+  point->radiusY = std::max(1.f, event->radius_y());
   point->rotationAngle = event->rotation_angle();
   point->force = event->force();