<http://webkit.org/b/116185>

Source/WebCore:

Reviewed by Anders Carlsson.

A Page's chrome() can never be null. Change Page::chrome() to return a reference to reflect this.
Also, make Page::m_chrome a const member variable so nobody will accidentally set it to null.

Source/WebKit/blackberry:

Reviewed by Anders Carlsson.

Source/WebKit/efl:

Reviewed by Anders Carlsson.

Source/WebKit/gtk:

Reviewed by Anders Carlsson.

Source/WebKit/mac:

Reviewed by Anders Carlsson.

Source/WebKit/qt:

Reviewed by Anders Carlsson.

Source/WebKit/win:

Reviewed by Anders Carlsson.

Source/WebKit2:

Reviewed by Anders Carlsson.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150214 268f45cc-cd09-0410-ab3c-d52691b4dbfc