Fix telemetry viewport calculations for gestures when zoomed in.

Fix telemetry viewport calculations for gestures when zoomed in.

The gesture code tries to calculate the bounding rect for a given
element relative to the viewport in order to send gestures to that
element. However, when the page is pinch-zoomed in, the gesture
code expects the bounding rect to be relative to the visual viewport,
that is, what the user sees. The current code was calculating this
incorrectly in the presence of pinch-zoom. In fact, it's impossible
to calculate correctly without adding additional information about
the visual viewport to the gpuBenchmarking extensions.

This CL depends on landing http://crrev.com/1866793003 and uses the
additional information to accurately calculate the element's rect
relative to the visual viewport.

BUG=chromium:564008

[bokan, 2016-04-07 03:49:27]

Description was changed from

==========
Fix viewport calculations in pinch gestures.

BUG=catapult:#
==========

to

==========
Fix viewport calculations in pinch gestures.

BUG=chromium:564008
==========

[bokan, 2016-04-07 16:20:52]

Description was changed from

==========
Fix viewport calculations in pinch gestures.

BUG=chromium:564008
==========

to

==========
Fix viewport calculations for gestures when zoomed in.

The gesture code tries to calculate the bounding rect for a given
element relative to the viewport in order to send gestures to that
element. However, when the page is pinch-zoomed in, the gesture
code expects the bounding rect to be relative to the visual viewport,
that is, what the user sees. The current code was calculating this
incorrectly in the presence of pinch-zoom. In fact, it's impossible
to calculate correctly without adding additional information about
the visual viewport to the gpuBenchmarking extensions.

This CL depends on landing http://crrev.com/1866793003 and uses the
additional information to accurately calculate the element's rect
relative to the visual viewport.

BUG=chromium:564008
==========

[bokan, 2016-04-07 21:37:52]

Description was changed from

==========
Fix viewport calculations for gestures when zoomed in.

The gesture code tries to calculate the bounding rect for a given
element relative to the viewport in order to send gestures to that
element. However, when the page is pinch-zoomed in, the gesture
code expects the bounding rect to be relative to the visual viewport,
that is, what the user sees. The current code was calculating this
incorrectly in the presence of pinch-zoom. In fact, it's impossible
to calculate correctly without adding additional information about
the visual viewport to the gpuBenchmarking extensions.

This CL depends on landing http://crrev.com/1866793003 and uses the
additional information to accurately calculate the element's rect
relative to the visual viewport.

BUG=chromium:564008
==========

to

==========
Fix telemetry viewport calculations for gestures when zoomed in.

The gesture code tries to calculate the bounding rect for a given
element relative to the viewport in order to send gestures to that
element. However, when the page is pinch-zoomed in, the gesture
code expects the bounding rect to be relative to the visual viewport,
that is, what the user sees. The current code was calculating this
incorrectly in the presence of pinch-zoom. In fact, it's impossible
to calculate correctly without adding additional information about
the visual viewport to the gpuBenchmarking extensions.

This CL depends on landing http://crrev.com/1866793003 and uses the
additional information to accurately calculate the element's rect
relative to the visual viewport.

BUG=chromium:564008
==========