Move caret to correct position when dir=auto for space and LTR text following RTL text.

In getPositionAndOffset, previous block was used when space is entered for dir=auto. While for dir=auto text using previous block gives wrong caret position, which was leading to caret offset not calculated.  In case of RTL, previous inline box position is used.

Since auto scenario, combines RTL and LTR text. In renderText, only render block direction is used. New condition has been added in RenderText to test if dir=auto, then use inlineBlock bidiLevel to decide about caret position rendering.

R=leviw, eae
BUG=296847
TEST=Direction auto tests covering move caret position to the right when
LTR text is entered and adding RTL text to move caret to the left.

Review URL: https://codereview.chromium.org/541823003

git-svn-id: svn://svn.chromium.org/blink/trunk@181701 bbb929c8-8fbe-4397-9dbb-9b2b20218538