[DevTools] Interactive test for DevTools touch emulation.

content/browser/renderer_host/input/touch_emulator.cc

Index: content/browser/renderer_host/input/touch_emulator.cc
diff --git a/content/browser/renderer_host/input/touch_emulator.cc b/content/browser/renderer_host/input/touch_emulator.cc
index 785935f3d9a9a2ce41cc2dbc89b3a766db51cdbe..938944c78bb9d02dcba1314531657ab7f5988bbd 100644
--- a/content/browser/renderer_host/input/touch_emulator.cc
+++ b/content/browser/renderer_host/input/touch_emulator.cc
@@ -341,6 +341,11 @@ bool TouchEmulator::FillTouchEventAndPoint(const WebMouseEvent& mouse_event) {
 
   touch_event_.touchesLength = 1;
   touch_event_.timeStampSeconds = mouse_event.timeStampSeconds;
+  if (!touch_event_.timeStampSeconds) {
+    // Gesture detector does not tolerate null timestamps generated in tests.
+    touch_event_.timeStampSeconds =
+        (base::TimeTicks::Now() - base::TimeTicks()).InSecondsF();
+  }
   touch_event_.modifiers = mouse_event.modifiers;
 
   WebTouchPoint& point = touch_event_.touches[0];