Introduce composed tree version of VisiblePosition

Introduce composed tree version of VisiblePosition

This patch introduces composed tree version of |VisiblePosition| called
|VisiblePositionInComposedTree| with glue function
|createVisiblePositionInDOMTree()|, which is a stub function for applying
DOM tree version of functions in "VisibleUnits.cpp", e.g. |isLogicalEndOfLine()|
|nextPositionOf()| and so on, for making patch size smaller.

This patch is a preparation of making selection to handle granularity for web
component, http://crrev.com/1277863002

BUG=513568
TEST=n/a; no behavior changes

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201859

[yosin_UTC9, 2015-09-04 12:03:04]

yosin@chromium.org changed reviewers:
+ hajimehoshi@chromium.org, tkent@chromium.org, yoichio@chromium.org

[yosin_UTC9, 2015-09-04 12:03:05]

PTAL

[yoichio, 2015-09-07 02:12:21]

1. I don't why do we need |createVisiblePositionInDOMTree| instead of 
|createVisiblePosition|.

2. This CL change VisiblePosition instanciate with
|createWithoutCanonicalization|
 to |create|. Is that OK?


3. Since |createWithoutCanonicalization| is used only by VisiblePostion, I
suggest
 move it to static in cpp first.

[yosin_UTC9, 2015-09-07 02:27:07]

On 2015/09/07 02:12:21, yoichio wrote:
> 1. I don't why do we need |createVisiblePositionInDOMTree| instead of 
> |createVisiblePosition|.
This is for making patch size small.

When we use |createVisiblePosition()|, we need to have composed tree
version of |nextPositionOf()|, |isLogicalEndOfLine()| functions and
more.


> 2. This CL change VisiblePosition instanciate with
> |createWithoutCanonicalization|
>  to |create|. Is that OK?
The purpose of |createWithoutCanonicalization()| is to call private ctor
of |VisiblePosition| for composed tree version of |createVisiblePosition|
which needs to map a position canonicalized in composed tree to DOM
position. |VisiblePosition::create()| does canonicalization and
create instance for DOM tree and composed tree version.

 
> 3. Since |createWithoutCanonicalization| is used only by VisiblePostion, I
> suggest
>  move it to static in cpp first.

|createWithoutCanonicalization()| needs to call private ctor. Rather than
|createWithoutCanonicalization()| as friend of |VisiblePositionTemplate|,
using static member function w/ TODO may simpler. It is going away by
this CL.

[yoichio, 2015-09-07 03:39:44]

On 2015/09/07 02:27:07, Yosi_UTC9 wrote:
> On 2015/09/07 02:12:21, yoichio wrote:
> > 1. I don't why do we need |createVisiblePositionInDOMTree| instead of 
> > |createVisiblePosition|.
> This is for making patch size small.
> 
> When we use |createVisiblePosition()|, we need to have composed tree
> version of |nextPositionOf()|, |isLogicalEndOfLine()| functions and
> more.
> 
My question is that |VisiblePosition createVisiblePosition(const Position&
position, TextAffinity affinity)|
 and |VisiblePosition createVisiblePositionInDOMTree(const Position& position,
TextAffinity affinity)|
 do exactly same thing. Why?

[yoichio, 2015-09-07 04:20:59]

lgtm

[yosin_UTC9, 2015-09-07 05:05:20]

On 2015/09/07 03:39:44, yoichio wrote:
> On 2015/09/07 02:27:07, Yosi_UTC9 wrote:
> > On 2015/09/07 02:12:21, yoichio wrote:
> > > 1. I don't why do we need |createVisiblePositionInDOMTree| instead of 
> > > |createVisiblePosition|.
> > This is for making patch size small.
> > 
> > When we use |createVisiblePosition()|, we need to have composed tree
> > version of |nextPositionOf()|, |isLogicalEndOfLine()| functions and
> > more.
> > 
> My question is that |VisiblePosition createVisiblePosition(const Position&
> position, TextAffinity affinity)|
>  and |VisiblePosition createVisiblePositionInDOMTree(const Position& position,
> TextAffinity affinity)|
>  do exactly same thing. Why?

createVisiblePositionInDOMTree() is a temporary function will be renamed to 
createVisiblePosition(). It is introduced for making size of this patch small
rather than including composed tree version of this patch.

I and yoichio@ also discussed in this offline.

[tkent, 2015-09-07 05:49:48]

rs lgtm

[yosin_UTC9, 2015-09-07 06:02:45]

The CQ bit was checked by yosin@chromium.org

[yosin_UTC9, 2015-09-07 06:02:45]

The patchset sent to the CQ was uploaded after l-g-t-m from yoichio@chromium.org
Link to the patchset: https://codereview.chromium.org/1319753004/#ps20001
(title: "2015-09-07T14:06:02 Rebase for VisibleSelectionChangeObserver and
PendingSelection::commit")

[commit-bot: I haz the power, 2015-09-07 06:02:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1319753004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1319753004/20001

[commit-bot: I haz the power, 2015-09-07 06:19:56]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201859