The first step is just to keep track of the number of rows and columns separately, even if we don't populate them.

My suggestion is to start with the first line of code that takes the (rows, columns) from the braille display and turns it into a single cell count, and fix it to keep track of both rows and columns, then use the compiler to figure out what needs to change as a result of that.

Open chrome/browser/extensions/api/braille_display_private/brlapi_connection.cc and edit GetDisplaySize. Make it return rows and columns instead of just a size (see where it currently sets size to columns * rows).

Then try to compile Chrome and use the compile errors as a clue to figure out what to fix next.

At some point you will encounter braille_display_private.h and braille_display_private.cc, note that these are auto-generated from this file:

chrome/common/extensions/api/braille_display_private.idl

You will want to modify (long? textCellCount;) and replace it with rows and columns instead.

When you get all the way back to braille_display_manager.js, don't try to implement full support for multi-line, just use the number of columns instead of the total number of text cells.

The goal of this change is to update a bunch of data structures and make the code multi-line "aware", without actually changing any behavior for existing braille displays and without breaking anything.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ffd46520fa89b84acb6a829f1b3d3b183477f1ad

commit ffd46520fa89b84acb6a829f1b3d3b183477f1ad
Author: ultimatedbz <ultimatedbz@google.com>
Date: Fri Nov 11 01:30:08 2016

Add multiline braille support.

Added code to take in 1D array and also row and column count.

Code compiles up to auto generated code. Cannot figure out how to generate a vector of vectors of chars. Also don't know where is appropriate to add in col and row information. Also do no know if input is assumed to be 1D or 2D

BUG=651570
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2401393003
Cr-Commit-Position: refs/heads/master@{#431444}

[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/braille_controller.h
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/braille_controller_brlapi.cc
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/braille_controller_brlapi.h
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/braille_display_private_api.cc
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/braille_display_private_apitest.cc
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/brlapi_connection.cc
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/brlapi_connection.h
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/mock_braille_controller.cc
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/stub_braille_controller.cc
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/extensions/api/braille_display_private/stub_braille_controller.h
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/resources/chromeos/chromevox/braille/braille_display_manager.js
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/resources/chromeos/chromevox/braille/braille_display_manager_test.unitjs
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/browser/resources/chromeos/chromevox/host/chrome/externs.js
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/common/extensions/api/braille_display_private.idl
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/test/data/extensions/api_test/braille_display_private/display_state_changes/test.js
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/test/data/extensions/api_test/braille_display_private/key_events/test.js
[modify] https://crrev.com/ffd46520fa89b84acb6a829f1b3d3b183477f1ad/chrome/test/data/extensions/api_test/braille_display_private/write_dots/test.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/5478c13533511f3ae67491ef23d3adfd9c48eb2c

commit 5478c13533511f3ae67491ef23d3adfd9c48eb2c
Author: Dominic Mazzoni <dmazzoni@chromium.org>
Date: Thu Feb 23 18:14:30 2017

Add experimental drivers for Dot Pad and Bristol Canute braille displays.

BUG=chromium:651570
TEST=Manually flashed and tested braille devices

Change-Id: I5e3cf95b1cb5d4f397de433732c29ab3e18b877f
Reviewed-on: https://chromium-review.googlesource.com/434798
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Dominic Mazzoni <dmazzoni@chromium.org>

[modify] https://crrev.com/5478c13533511f3ae67491ef23d3adfd9c48eb2c/app-accessibility/brltty/brltty.bashrc
[rename] https://crrev.com/5478c13533511f3ae67491ef23d3adfd9c48eb2c/app-accessibility/brltty/brltty-5.4-r4.ebuild
[add] https://crrev.com/5478c13533511f3ae67491ef23d3adfd9c48eb2c/app-accessibility/brltty/files/brltty-5.4-canute.patch
[add] https://crrev.com/5478c13533511f3ae67491ef23d3adfd9c48eb2c/app-accessibility/brltty/files/brltty-5.4-dot.patch

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

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