Remove unnecessary font list creation in AppListItemView.

Remove unnecessary font list creation in AppListItemView.

This CL improves the app list startup time on non-Linux platforms. A new
FontList object was being unnecessarily created on every AppListItemView
which forced recalculations of otherwise cached values.

This was most noticeable on ChromeOS where the app list is
rebuilt every time it is shown.

BUG=415389
Committed: https://crrev.com/b5b43219131ca9fed3aa6841085ef67de82e229f
Cr-Commit-Position: refs/heads/master@{#295663}

[calamity, 2014-09-18 01:50:40]

calamity@chromium.org changed reviewers:
+ tapted@chromium.org

[tapted, 2014-09-18 01:56:45]

https://codereview.chromium.org/574983002/diff/1/ui/app_list/views/app_list_i...
File ui/app_list/views/app_list_item_view.cc (right):

https://codereview.chromium.org/574983002/diff/1/ui/app_list/views/app_list_i...
ui/app_list/views/app_list_item_view.cc:96: font_list =
font_list.DeriveWithSizeDelta(kFontSizeDelta);
assigning to a const reference? pretty sure that shouldn't work :p

https://codereview.chromium.org/574983002/diff/1/ui/app_list/views/app_list_i...
ui/app_list/views/app_list_item_view.cc:98: title_->SetFontList(font_list);
nit: I think I liked the #ifdefs being just around the constant... what about

  const gfx::FontList& font_list = rb.GetFontList(kItemTextFontStyle);
  title_->SetFontList(kFontSizeDelta == 0 ?
      font_list : font_list.DeriveWithSizeDelta(kFontSizeDelta));

[calamity, 2014-09-18 07:01:49]

Patchset #2 (id:20001) has been deleted

[calamity, 2014-09-18 07:48:04]

Used a static dealy as discussed.

[tapted, 2014-09-18 09:48:09]

lgtm

[calamity, 2014-09-19 04:23:27]

The CQ bit was checked by calamity@chromium.org

[commit-bot: I haz the power, 2014-09-19 04:24:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/574983002/40001

[commit-bot: I haz the power, 2014-09-19 05:27:46]

Committed patchset #2 (id:40001) as a1015513db855e36282b82cfc48c2eaa825c0dc2

[commit-bot: I haz the power, 2014-09-19 05:28:42]

Patchset 2 (id:??) landed as
https://crrev.com/b5b43219131ca9fed3aa6841085ef67de82e229f
Cr-Commit-Position: refs/heads/master@{#295663}