Touch emulator: overwrite timestamps from mouse event with current time.

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 42b43106c7861847092ca29d19443a0b0cdce726..c43b4bd5d719c87aa24f702c77d10a91644a3a44 100644
--- a/content/browser/renderer_host/input/touch_emulator.cc
+++ b/content/browser/renderer_host/input/touch_emulator.cc
@@ -361,6 +361,16 @@ bool TouchEmulator::FillTouchEventAndPoint(const WebMouseEvent& mouse_event) {
   WebTouchEventTraits::ResetTypeAndTouchStates(
       eventType, mouse_event.timeStampSeconds, &touch_event_);
 
+  // On some platforms mouse event's timestamp does not necessarily relate to
+  // the system time at all, so use base::TimeTicks::HighResNow() if possible,
+  // or base::TimeTicks::Now() otherwise.
+  base::TimeTicks now;
+  if (base::TimeTicks::IsHighResNowFastAndReliable())
+    now = base::TimeTicks::HighResNow();
+  else
+    now = base::TimeTicks::Now();
+  touch_event_.timeStampSeconds = (now - base::TimeTicks()).InSecondsF();
+
   WebTouchPoint& point = touch_event_.touches[0];
   point.id = 0;
   point.radiusX = point.radiusY = 1.f;