The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c5707d4d2131cf90f2fe8c9887a1c95c83a12812

commit c5707d4d2131cf90f2fe8c9887a1c95c83a12812
Author: lanwei <lanwei@chromium.org>
Date: Wed Jun 08 22:50:00 2016

Use monotonic time to record the touch input latency in Blink.

Since PlatformEvent uses monotonical time stamp, we should use monotonicallyIncreasingTime
instead of currentTime to record the touch event latency in Blink.

BUG= 617984 

Review-Url: https://codereview.chromium.org/2044923004
Cr-Commit-Position: refs/heads/master@{#398712}

[modify] https://crrev.com/c5707d4d2131cf90f2fe8c9887a1c95c83a12812/third_party/WebKit/Source/core/input/TouchEventManager.cpp

Your change meets the bar and is auto-approved for M52 (branch: 2743)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/da0f532810ea5326996237262c0e0711d7c0e737

commit da0f532810ea5326996237262c0e0711d7c0e737
Author: lanwei <lanwei@chromium.org>
Date: Thu Jun 09 22:10:03 2016

Use monotonic time to record the touch input latency in Blink.

Since PlatformEvent uses monotonical time stamp, we should use monotonicallyIncreasingTime
instead of currentTime to record the touch event latency in Blink.

BUG= 617984 

Review-Url: https://codereview.chromium.org/2044923004
Cr-Commit-Position: refs/heads/master@{#398712}
(cherry picked from commit c5707d4d2131cf90f2fe8c9887a1c95c83a12812)

Review URL: https://codereview.chromium.org/2059523002 .

Cr-Commit-Position: refs/branch-heads/2743@{#301}
Cr-Branched-From: 2b3ae3b8090361f8af5a611712fc1a5ab2de53cb-refs/heads/master@{#394939}

[modify] https://crrev.com/da0f532810ea5326996237262c0e0711d7c0e737/third_party/WebKit/Source/core/input/TouchEventManager.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/da0f532810ea5326996237262c0e0711d7c0e737

commit da0f532810ea5326996237262c0e0711d7c0e737
Author: lanwei <lanwei@chromium.org>
Date: Thu Jun 09 22:10:03 2016

Use monotonic time to record the touch input latency in Blink.

Since PlatformEvent uses monotonical time stamp, we should use monotonicallyIncreasingTime
instead of currentTime to record the touch event latency in Blink.

BUG= 617984 

Review-Url: https://codereview.chromium.org/2044923004
Cr-Commit-Position: refs/heads/master@{#398712}
(cherry picked from commit c5707d4d2131cf90f2fe8c9887a1c95c83a12812)

Review URL: https://codereview.chromium.org/2059523002 .

Cr-Commit-Position: refs/branch-heads/2743@{#301}
Cr-Branched-From: 2b3ae3b8090361f8af5a611712fc1a5ab2de53cb-refs/heads/master@{#394939}

[modify] https://crrev.com/da0f532810ea5326996237262c0e0711d7c0e737/third_party/WebKit/Source/core/input/TouchEventManager.cpp

lanwei@, can you please let us know if this can be tested manually so that we can verify it at our end ?

Please take a look at chrome://histograms/Event.Touch.TouchLatencyAfterPageLoad and Event.Touch.TouchLatencyBeforePageLoad to see if the latencies have the appropriate values.