<https://webkit.org/b/120702>

Reviewed by Anders Carlsson.

Move ImageQualityController to its own files and add a RenderView::imageQualityController()
getter instead of using a global map for all render trees.

This avoids having to unregister every renderer (well, every RenderBoxModelObject) from the
global hash map during render tree teardown.

It also simplifies the live resize optimization a bit since it can now short-circuit if
the RenderView's FrameView is being resized. (Previously there could be any number of
RenderViews present in the map.)

* CMakeLists.txt:
* GNUmakefile.list.am:
* Target.pri:
* WebCore.vcxproj/WebCore.vcxproj:
* WebCore.xcodeproj/project.pbxproj:
* rendering/ImageQualityController.cpp: Added.
* rendering/ImageQualityController.h: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@155077 268f45cc-cd09-0410-ab3c-d52691b4dbfc