Combine background repaint conditions in RenderStyle and RenderObject

Combined RenderStyle::needsFullRepaintOnContainer(Width|Height)Change
and local function mustRepaintFillLayers() in RenderObject.cpp into
RenderObject::mustRepaintFillLayersOn(Width|Height)Change.

Added missing logics of the original mustRepaintFillLayers():
- repaint if background-repeat is not repeat and no-repeat;
- repaint if background-position is not left or top origin;
- don't repaint if background-position is of fixed length;

TEST=fast/repaint/background-resize-width.html
TEST=fast/repaint/background-resize-height.html

Review URL: https://codereview.chromium.org/306483011

git-svn-id: svn://svn.chromium.org/blink/trunk@175172 bbb929c8-8fbe-4397-9dbb-9b2b20218538