ash: Refactor of TouchTransformerController

ash: Refactor of TouchTransformerController

In preparation for reusing touch transformations for transforming on
screen stylus events into display co-ordinates this CL does a simple
refactor of TouchTransformerController.

This change will be followed up by a subsequent CL that enables support
for having multiple touchscreens per display with the per-device looping
happening in the new methods: UpdateTouchRadius() and
UpdateTouchTransform().

TEST=ash_unittests passes, interactive testing on link_freon in mirrored
and non-mirrored mode.
BUG=448467
Committed: https://crrev.com/73b49ca2f1c855ebdd383255f523721fb862526d
Cr-Commit-Position: refs/heads/master@{#329830}

[robert.bradford, 2015-05-13 14:28:11]

robert.bradford@intel.com changed reviewers:
+ derat@chromium.org

[robert.bradford, 2015-05-13 14:28:11]

robert.bradford@intel.com changed required reviewers:
+ derat@chromium.org

[robert.bradford, 2015-05-13 14:28:12]

Hi Daniel, please take a look at this change.

[robert.bradford, 2015-05-13 14:28:26]

The CQ bit was checked by robert.bradford@intel.com to run a CQ dry run

[commit-bot: I haz the power, 2015-05-13 14:28:37]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1130983005/1

[commit-bot: I haz the power, 2015-05-13 15:09:45]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-05-13 15:09:46]

Dry run: This issue passed the CQ dry run.

[Daniel Erat, 2015-05-13 15:37:46]

derat@chromium.org changed reviewers:
+ dnicoara@chromium.org

[Daniel Erat, 2015-05-13 15:37:47]

i don't have much state on this file; adding dnicoara@, who probably does. i
think that adding an ash/touch/OWNERS file would make sense.

i'm happy to approve after the review, although i'll be out of the office for a
while starting tomorrow.

[Daniel Erat, 2015-05-13 15:41:23]

one nit

https://codereview.chromium.org/1130983005/diff/1/ash/touch/touch_transformer...
File ash/touch/touch_transformer_controller.h (right):

https://codereview.chromium.org/1130983005/diff/1/ash/touch/touch_transformer...
ash/touch/touch_transformer_controller.h:64: // For the provided |display|
update the touch touch radius mapping.
you have an extra "touch" in this comment

[dnicoara, 2015-05-13 16:04:17]

lgtm ... I'm guessing adding support for more touch devices will make this more
complex.

https://codereview.chromium.org/1130983005/diff/1/ash/touch/touch_transformer...
File ash/touch/touch_transformer_controller.h (right):

https://codereview.chromium.org/1130983005/diff/1/ash/touch/touch_transformer...
ash/touch/touch_transformer_controller.h:70: void UpdateTouchTransform(int64_t
target_display_id,
nit: Would you mind adding a description on what each parameter represent and
how they are related?

[robert.bradford, 2015-05-13 16:49:18]

Thanks derat@ & dnicoara@ i've fixed the comments.

[Daniel Erat, 2015-05-13 19:07:54]

lgtm

[robert.bradford, 2015-05-14 11:18:34]

The CQ bit was checked by robert.bradford@intel.com

[robert.bradford, 2015-05-14 11:18:35]

The patchset sent to the CQ was uploaded after l-g-t-m from
dnicoara@chromium.org
Link to the patchset: https://codereview.chromium.org/1130983005/#ps20001
(title: "Address review feedback")

[commit-bot: I haz the power, 2015-05-14 11:18:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1130983005/20001

[commit-bot: I haz the power, 2015-05-14 11:48:03]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-14 11:48:43]

Patchset 2 (id:??) landed as
https://crrev.com/73b49ca2f1c855ebdd383255f523721fb862526d
Cr-Commit-Position: refs/heads/master@{#329830}