I ran a custom build Chrome without 10s delay to check if the new wake-up based throttling code in the latest Chrome can avoid the problems with  crbug.com/649942 .

As far as I can perceive, Tampermonkey and Feedly Notifier do not show any performance regression.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/aa449b76a4ea265126b7c3bdd5084589e5b66adf

commit aa449b76a4ea265126b7c3bdd5084589e5b66adf
Author: Takashi Toyoshima <toyoshim@chromium.org>
Date: Thu Jun 22 05:33:41 2017

Remove 10s delay in throttling backgrounded tabs

The background tab throttling is delayed by 10s mainly to solve the
slow extension pop-up issue ( crbug.com/649942 ).
But, now that Blink scheduler has the he new wake-up based throttling,
this workaround should not be needed any more.

This patch virtually reverts https://codereview.chromium.org/2620743002/

BUG= 734165 
TEST=manually check if this does not cause the extension pop-up issue.

Change-Id: Id8459e43340e50ce48c0d443d6bd8a9bcaee64a6
Reviewed-on: https://chromium-review.googlesource.com/543095
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#481449}
[modify] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/LayoutTests/TestExpectations
[add] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/LayoutTests/fast/dom/timer-throttling-hidden-page-expected.txt
[add] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/LayoutTests/fast/dom/timer-throttling-hidden-page.html
[modify] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/Source/platform/WebFrameScheduler.h
[modify] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/Source/platform/scheduler/renderer/web_frame_scheduler_impl.cc
[modify] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/Source/platform/scheduler/renderer/web_frame_scheduler_impl.h
[modify] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/Source/platform/scheduler/renderer/web_frame_scheduler_impl_unittest.cc
[modify] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.cc
[modify] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl.h
[modify] https://crrev.com/aa449b76a4ea265126b7c3bdd5084589e5b66adf/third_party/WebKit/Source/platform/scheduler/renderer/web_view_scheduler_impl_unittest.cc