Rename HTMLInputElement::imageLoader() to ensureImageLoader()

Make clear that imageLoader is potentially constructing the
ImageLoader by renaming to ensureImageLoader. Also rename
hasImageLoader to imageLoader and make it return a pointer,
so it can be used both to check if the ImageLoader is created
as well as use it if not null.

http://trac.webkit.org/changeset/175764

Review URL: https://codereview.chromium.org/715633005

git-svn-id: svn://svn.chromium.org/blink/trunk@185143 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Set relayoutChildren to 'true' only if size change happens in Table

This patch passes 'true' value for layoutPositionedObjects() in case of size change.
It helps to avoid unneccessary setChildNeedsLayout() and setPreferredLogicalWidthsDirty() calls.

Review URL: https://codereview.chromium.org/714933002

git-svn-id: svn://svn.chromium.org/blink/trunk@185144 bbb929c8-8fbe-4397-9dbb-9b2b20218538