Extract HTMLImportLoader from LinkImport

Extract HTMLImportLoader from LinkImport

This change extract loading facility and ownership of imported document
from LinkImport to HTMLImportLoader, by doing this, sharing import
between <link>s can be represented in straightforward way.

Before this change, all shared imports of an URL become unavailable once
the first <link> is removed from tree. This extraction fixes the problem.

BUG=240592
TEST=import-shared-remove.html
R=dglazkov
R=dominicc

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=152698

[Hajime Morrita, 2013-06-19 02:23:23]

Could you take a look?
This is a preparation for implementing subimport.

[dglazkov, 2013-06-19 02:53:52]

lgtm + nit:

https://codereview.chromium.org/17137008/diff/1/Source/core/html/HTMLImportsC...
File Source/core/html/HTMLImportsController.h (right):

https://codereview.chromium.org/17137008/diff/1/Source/core/html/HTMLImportsC...
Source/core/html/HTMLImportsController.h:49: class LinkImport : public
LinkResource, CachedResourceClient {
Does this still need to be a CachedResourceClient?

[Hajime Morrita, 2013-06-19 03:37:00]

On 2013/06/19 02:53:52, Dimitri Glazkov wrote:
> lgtm + nit:
> 
>
https://codereview.chromium.org/17137008/diff/1/Source/core/html/HTMLImportsC...
> File Source/core/html/HTMLImportsController.h (right):
> 
>
https://codereview.chromium.org/17137008/diff/1/Source/core/html/HTMLImportsC...
> Source/core/html/HTMLImportsController.h:49: class LinkImport : public
> LinkResource, CachedResourceClient {
> Does this still need to be a CachedResourceClient?
No. Thanks for the catch! and review! Will revise and land.

[commit-bot: I haz the power, 2013-06-19 03:40:07]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/morrita@chromium.org/17137008/6001

[commit-bot: I haz the power, 2013-06-19 05:36:22]

Change committed as 152698