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

On some platfroms, mouse events come with a bad timestamp, which leads to
awkward time-dependent gestures. For example, fling animation may be almost
instant.
Using base::TimeTicks::Now() is good enough for emulation purposes, because
emulator spawns new events itself.

BUG=367156

Review URL: https://codereview.chromium.org/250923005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@266548 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/renderer_host/input/touch_emulator.cc

@@ -316,7 +316,7 @@ void TouchEmulator::PinchEnd(const WebGestureEvent& event) {
   client_->ForwardGestureEvent(pinch_event_);
 }
 
-void TouchEmulator::FillPinchEvent(const WebInputEvent& event) {
+void TouchEmulator::FillPinchEvent(const WebGestureEvent& event) {
   pinch_event_.timeStampSeconds = event.timeStampSeconds;
   pinch_event_.modifiers = event.modifiers;
   pinch_event_.sourceDevice = blink::WebGestureEvent::Touchscreen;
@@ -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;

content/browser/renderer_host/input/touch_emulator.h

@@ -48,7 +48,7 @@ class CONTENT_EXPORT TouchEmulator : public ui::GestureProviderClient {
   bool InPinchGestureMode() const;
 
   bool FillTouchEventAndPoint(const blink::WebMouseEvent& mouse_event);
-  void FillPinchEvent(const blink::WebInputEvent& event);
+  void FillPinchEvent(const blink::WebGestureEvent& event);
 
   // The following methods generate and pass gesture events to the renderer.
   void PinchBegin(const blink::WebGestureEvent& event);

content/browser/renderer_host/input/touch_emulator_unittest.cc

@@ -202,7 +202,7 @@ TEST_F(TouchEmulatorTest, Touch) {
   MouseUp(200, 200);
   EXPECT_EQ(
       "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate"
-      " TouchEnd GestureScrollEnd",
+      " TouchEnd GestureFlingStart",
       ExpectedEvents());
 }
 
@@ -214,13 +214,13 @@ TEST_F(TouchEmulatorTest, MultipleTouches) {
   MouseUp(200, 200);
   EXPECT_EQ(
       "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate"
-      " TouchEnd GestureScrollEnd",
+      " TouchEnd GestureFlingStart",
       ExpectedEvents());
   MouseMove(300, 200);
   MouseMove(200, 200);
   EXPECT_EQ("", ExpectedEvents());
   MouseDown(300, 200);
-  EXPECT_EQ("TouchStart GestureTapDown", ExpectedEvents());
+  EXPECT_EQ("TouchStart GestureFlingCancel GestureTapDown", ExpectedEvents());
   MouseDrag(300, 300);
   EXPECT_EQ(
       "TouchMove GestureTapCancel GestureScrollBegin GestureScrollUpdate",