Hide canonicalPosition in VisiblePosition from header file

Hide canonicalPosition in VisiblePosition from header file

This patch makes static member function |VisiblePosition::canonicalPosition| to
static function in "VisiblePosition.cpp" for code health by limiting visibility.

Since following patch make |canonicalPosition()| to be a template funciton to
make |VisiblePosition| to work with both DOM tree position and composed tree
position for selection for web component, we don't want to have template
declaration, which is implementation details and redundant information for
clients of |VisiblePostion|, in private section of header file.

a preparation of converting
|canonicalPosition| to a template function to make |VisibilePosition| to work
with both a position in DOM tree and composed tree.

This patch is result of collaboration work with hajimehoshi@chromium.org
for selection of web components. After this patch, we are going to
implement another strategies for the composed tree. We've already
prepared that at http://crrev.com/1106433002.

BUG=275851
TEST=n/a; No behavior changes.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197430

[yosin_UTC9, 2015-06-19 03:49:09]

yosin@chromium.org changed reviewers:
+ tkent@chromium.org

[yosin_UTC9, 2015-06-19 03:49:17]

PTAL

[tkent, 2015-06-19 03:53:58]

https://codereview.chromium.org/1191193002/diff/1/Source/core/editing/Visible...
File Source/core/editing/VisiblePosition.cpp (right):

https://codereview.chromium.org/1191193002/diff/1/Source/core/editing/Visible...
Source/core/editing/VisiblePosition.cpp:61: static Position
canonicalPosition(const Position& passedPosition);
Usually we don't add forward declaration for a static function.  But the
function is too large to move here.
so, lgtm.

[yosin_UTC9, 2015-06-19 04:17:51]

The CQ bit was checked by yosin@chromium.org

[commit-bot: I haz the power, 2015-06-19 04:18:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1191193002/1

[yosin_UTC9, 2015-06-19 04:18:29]

On 2015/06/19 03:53:58, tkent wrote:
>
https://codereview.chromium.org/1191193002/diff/1/Source/core/editing/Visible...
> File Source/core/editing/VisiblePosition.cpp (right):
> 
>
https://codereview.chromium.org/1191193002/diff/1/Source/core/editing/Visible...
> Source/core/editing/VisiblePosition.cpp:61: static Position
> canonicalPosition(const Position& passedPosition);
> Usually we don't add forward declaration for a static function.  But the
> function is too large to move here.
> so, lgtm.

I'll make follow up patch to change code layout to get rid of forward function
declaration.

[commit-bot: I haz the power, 2015-06-19 04:22:32]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197430