Introduce composed tree version of leftPositionOf()

Introduce composed tree version of leftPositionOf()

This patch introduces composed tree version of |leftPositionOf()|
by templatizing original |leftPositionOf()| to work both DOM tree
position and composed tree position version for introducing composed tree
version of |VisibleSelection| class.

This patch also introduces |createVisiblePosition()| for
|PositionInComposdTreeWithAffinity| and templaizes
|honorEditingBoundaryAtOrAfter()| and |leftVisuallyDistinctCandidate()| used
by |leftPositionOf()|.

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=201954

[yosin_UTC9, 2015-09-08 07:44:36]

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

[yosin_UTC9, 2015-09-08 07:49:13]

PTAL

[yoichio, 2015-09-08 08:26:42]

https://codereview.chromium.org/1326313002/diff/1/Source/core/editing/Visible...
File Source/core/editing/VisibleUnitsTest.cpp (right):

https://codereview.chromium.org/1326313002/diff/1/Source/core/editing/Visible...
Source/core/editing/VisibleUnitsTest.cpp:126:
EXPECT_EQ(Position(two->firstChild(), 1),
leftPositionOf(createVisiblePosition(Position(one, 0))).deepEquivalent());
(two->firstChild(), 1) is not left of Position(one, 0).

[yosin_UTC9, 2015-09-08 08:37:31]

https://codereview.chromium.org/1326313002/diff/1/Source/core/editing/Visible...
File Source/core/editing/VisibleUnitsTest.cpp (right):

https://codereview.chromium.org/1326313002/diff/1/Source/core/editing/Visible...
Source/core/editing/VisibleUnitsTest.cpp:126:
EXPECT_EQ(Position(two->firstChild(), 1),
leftPositionOf(createVisiblePosition(Position(one, 0))).deepEquivalent());
On 2015/09/08 08:26:42, yoichio wrote:
> (two->firstChild(), 1) is not left of Position(one, 0).

Since, leftVisuallyDistinctCandidate() which called by leftPosition() scans
layout tree in addition to DOM tree, e.g. InlineBox::prevLeafChild().

This is reason why DOM tree version of leftPositionOf() returns "22" where
left of "1" in layout tree.

[yoichio, 2015-09-09 02:03:54]

https://codereview.chromium.org/1326313002/diff/1/Source/core/editing/Visible...
File Source/core/editing/VisibleUnitsTest.cpp (right):

https://codereview.chromium.org/1326313002/diff/1/Source/core/editing/Visible...
Source/core/editing/VisibleUnitsTest.cpp:126:
EXPECT_EQ(Position(two->firstChild(), 1),
leftPositionOf(createVisiblePosition(Position(one, 0))).deepEquivalent());
On 2015/09/08 08:37:31, Yosi_UTC9 wrote:
> On 2015/09/08 08:26:42, yoichio wrote:
> > (two->firstChild(), 1) is not left of Position(one, 0).
> 
> Since, leftVisuallyDistinctCandidate() which called by leftPosition() scans
> layout tree in addition to DOM tree, e.g. InlineBox::prevLeafChild().
> 
> This is reason why DOM tree version of leftPositionOf() returns "22" where
> left of "1" in layout tree.
Layout tree is composed tree?
If leftPositionOf refers a composed tree,
leftPositionOf("VisialPositionInDOMTree") doesn't make sense.
Or VisialPositionInDOMTree itself doesn't make sense?

[yoichio, 2015-09-09 02:34:19]

LGTM
Please describe this 'strange' behavior not always returning 'left' to .h.

[yosin_UTC9, 2015-09-09 03:52:26]

On 2015/09/09 02:03:54, yoichio wrote:
>
https://codereview.chromium.org/1326313002/diff/1/Source/core/editing/Visible...
> File Source/core/editing/VisibleUnitsTest.cpp (right):
> 
>
https://codereview.chromium.org/1326313002/diff/1/Source/core/editing/Visible...
> Source/core/editing/VisibleUnitsTest.cpp:126:
> EXPECT_EQ(Position(two->firstChild(), 1),
> leftPositionOf(createVisiblePosition(Position(one, 0))).deepEquivalent());
> On 2015/09/08 08:37:31, Yosi_UTC9 wrote:
> > On 2015/09/08 08:26:42, yoichio wrote:
> > > (two->firstChild(), 1) is not left of Position(one, 0).
> > 
> > Since, leftVisuallyDistinctCandidate() which called by leftPosition() scans
> > layout tree in addition to DOM tree, e.g. InlineBox::prevLeafChild().
> > 
> > This is reason why DOM tree version of leftPositionOf() returns "22" where
> > left of "1" in layout tree.
> Layout tree is composed tree?
> If leftPositionOf refers a composed tree,
> leftPositionOf("VisialPositionInDOMTree") doesn't make sense.
> Or VisialPositionInDOMTree itself doesn't make sense?

We're talking offline and agree that behavior of DOM version of
|leftPositionOf()|
is confusing.

[yosin_UTC9, 2015-09-09 03:52:36]

The CQ bit was checked by yosin@chromium.org

[yosin_UTC9, 2015-09-09 03:52:36]

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/1326313002/#ps20001
(title: "2015-09-09T12:49:11 Add a comment about DOM version of leftPositoin()
for composed tree")

[commit-bot: I haz the power, 2015-09-09 03:52:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1326313002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1326313002/20001

[commit-bot: I haz the power, 2015-09-09 05:04:19]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201954