OmniboxViewViews: Do not initialize ScopedObservers in the class declaration

See also: https://chromium-review.googlesource.com/1082316, which fixes the
same issue elsewhere.

GCC requires a full declaration for ScopedObserver's types to be present
when it is initialized in a class declaration:

    ../../base/scoped_observer.h: In instantiation of ‘void ScopedObserver<Source, Observer>::RemoveAll() [with Source = TemplateURLService; Observer = TemplateURLServiceObserver]’:
    ../../base/scoped_observer.h:26:14:   required from ‘ScopedObserver<Source, Observer>::~ScopedObserver() [with Source = TemplateURLService; Observer = TemplateURLServiceObserver]’
    ../../chrome/browser/ui/views/omnibox/omnibox_view_views.h:339:49:   required from here
    ../../base/scoped_observer.h:45:20: error: invalid use of incomplete type ‘class TemplateURLService’
           sources_[i]->RemoveObserver(observer_);
           ~~~~~~~~~~~~~^~~~~~~~~~~~~~
    In file included from ../../chrome/browser/ui/views/bookmarks/bookmark_bar_view.cc:31:0:
    ../../chrome/browser/search/search.h:12:7: note: forward declaration of ‘class TemplateURLService’
     class TemplateURLService;
           ^~~~~~~~~~~~~~~~~~

Fix it by moving the initialization to the class' member initialization
list.

Bug: 819294
Change-Id: I00d1a39254681b05bcfa4df56bc0b36f6fe318e4
Reviewed-on: https://chromium-review.googlesource.com/1084596
Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Cr-Commit-Position: refs/heads/master@{#564082}
2 files changed