Preserve monotonic timestamp when converting from Core -> Web Input Event.

This fixes a idiosyncrasy in blink input pipeline where when transforming
Core -> Web Input Events, WebInputEvent::timeStampSeconds field would get and
epoch timestamp value instead of a monotonic timestamp.

This occurs for any input event that gets passed to plugins  including Pepper
plugins.

The patch does the following:
- Use platform timestamp to populate WebInputEvent::timeStampSeconds
- Teach Pepper to expect monotonic time in theat field and remove all
unnecessary machinery in Pepper to convert event time.

BUG=538199

Review URL: https://codereview.chromium.org/1369333009

Cr-Commit-Position: refs/heads/master@{#352856}

3 files changed, 0 insertions, 50 deletions

diff --git a/ppapi/shared_impl/time_conversion.cc b/ppapi/shared_impl/time_conversion.cc
index 8da1483..651274a 100644
--- a/ppapi/shared_impl/time_conversion.cc
+++ b/ppapi/shared_impl/time_conversion.cc
@@ -6,25 +6,6 @@
 
 namespace ppapi {
 
-namespace {
-
-// Since WebKit doesn't use ticks for event times, we have to compute what
-// the time ticks would be assuming the wall clock time doesn't change.
-//
-// This should only be used for WebKit times which we can't change the
-// definition of.
-double GetTimeToTimeTicksDeltaInSeconds() {
-  static double time_to_ticks_delta_seconds = 0.0;
-  if (time_to_ticks_delta_seconds == 0.0) {
-    double wall_clock = TimeToPPTime(base::Time::Now());
-    double ticks = TimeTicksToPPTimeTicks(base::TimeTicks::Now());
-    time_to_ticks_delta_seconds = ticks - wall_clock;
-  }
-  return time_to_ticks_delta_seconds;
-}
-
-}  // namespace
-
 PP_Time TimeToPPTime(base::Time t) { return t.ToDoubleT(); }
 
 base::Time PPTimeToTime(PP_Time t) {
@@ -42,14 +23,6 @@ PP_TimeTicks TimeTicksToPPTimeTicks(base::TimeTicks t) {
          base::Time::kMicrosecondsPerSecond;
 }
 
-PP_TimeTicks EventTimeToPPTimeTicks(double event_time) {
-  return event_time + GetTimeToTimeTicksDeltaInSeconds();
-}
-
-double PPTimeTicksToEventTime(PP_TimeTicks t) {
-  return t - GetTimeToTimeTicksDeltaInSeconds();
-}
-
 double PPGetLocalTimeZoneOffset(const base::Time& time) {
   // Explode it to local time and then unexplode it as if it were UTC. Also
   // explode it to UTC and unexplode it (this avoids mismatching rounding or
diff --git a/ppapi/shared_impl/time_conversion.h b/ppapi/shared_impl/time_conversion.h
index bbc0865..888f1f2 100644
--- a/ppapi/shared_impl/time_conversion.h
+++ b/ppapi/shared_impl/time_conversion.h
@@ -16,13 +16,6 @@ PPAPI_SHARED_EXPORT base::Time PPTimeToTime(PP_Time t);
 
 PPAPI_SHARED_EXPORT PP_TimeTicks TimeTicksToPPTimeTicks(base::TimeTicks t);
 
-// Converts between WebKit event times and time ticks. WebKit event times are
-// currently expressed in terms of wall clock time. This function does the
-// proper mapping to time ticks, assuming the wall clock time doesn't change
-// (which isn't necessarily the case).
-PPAPI_SHARED_EXPORT PP_TimeTicks EventTimeToPPTimeTicks(double event_time);
-PPAPI_SHARED_EXPORT double PPTimeTicksToEventTime(PP_TimeTicks t);
-
 // Gets the local time zone offset for a given time. This works in the plugin
 // process only on Windows (the sandbox prevents this from working properly on
 // other platforms).
diff --git a/ppapi/shared_impl/time_conversion_unittest.cc b/ppapi/shared_impl/time_conversion_unittest.cc
index 1ec70bf..4d8c77e 100644
--- a/ppapi/shared_impl/time_conversion_unittest.cc
+++ b/ppapi/shared_impl/time_conversion_unittest.cc
@@ -34,22 +34,6 @@ TEST(TimeConversion, Time) {
   EXPECT_GE(kTimeSecondsSlop, fabs(converted_one_second_from_now - 1));
 }
 
-TEST(TimeConversion, EventTime) {
-  // Should be able to round-trip.
-  base::Time now = base::Time::Now();
-  double event_now = now.ToDoubleT();
-  double converted =
-      ppapi::EventTimeToPPTimeTicks(ppapi::PPTimeTicksToEventTime(event_now));
-  EXPECT_GE(kTimeSecondsSlop, fabs(converted - event_now));
-
-  // Units should be in seconds.
-  base::Time one_second_from_now = now + base::TimeDelta::FromSeconds(1);
-  double event_one_second_from_now = one_second_from_now.ToDoubleT();
-  EXPECT_GE(kTimeSecondsSlop,
-            1.0 - ppapi::EventTimeToPPTimeTicks(event_one_second_from_now) -
-                ppapi::EventTimeToPPTimeTicks(event_now));
-}
-
 TEST(TimeConversion, EpochTime) {
   // Should be able to round-trip from epoch time.
   base::Time epoch = base::Time::UnixEpoch();