Background color applied on a selection of text is lost when the selection is deleted

While deleting a selection, only inheritable style properties were
saved. Since background color is considered as noninheritable style
property, it was not being saved and hence was lost. Because of this
background color set on a selection of text was lost when the selection
was deleted and if new text is inserted after this it would not have
the background color set.

Before deleting a selection we should save all style properties applied
on that particular selection. Modified accordingly.

NOTE: This patch makes chrome behavior compatible with that of IE and FF.

Review URL: https://codereview.chromium.org/19477010

git-svn-id: svn://svn.chromium.org/blink/trunk@158906 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Delete fast/dom/adopt-node-crash-2.html.

This test is flaky. It relies on autofocus being synchronous. Instead,
it's now async due to lazyAttach. I could make the test unflaky by
adding document.body.offsetHeights in the right places, but I don't really
see the point given that this is a test for a crash that by design
can't happen anymore.

BUG=303321

Review URL: https://codereview.chromium.org/25903003

git-svn-id: svn://svn.chromium.org/blink/trunk@158908 bbb929c8-8fbe-4397-9dbb-9b2b20218538