Move logic for setPort to KURL

Now Location and DOMURLUtils use the same logic when setting the port.
The logic now matches the spec with regards to trailing junk.

There is one minor change in functionality. Setting port to '' used to
clear the port. Now we set the port to 0. This matches IE. Firefox
throws in this case and Presto ignored the put.

BUG=None

Review URL: https://codereview.chromium.org/28043003

git-svn-id: svn://svn.chromium.org/blink/trunk@159984 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix crash in TextFieldInputType::updatePlaceholderText when the password generation feature is enabled.

This is a regression by r159412 [1].

TextFieldInputType::updatePlaceholderText assumed |containerElement()| or
|innerTextElement()| is a child of a ShadowRoot. r159412 changed
input[type=password] so that it inserts another element between them.

[1] http://src.chromium.org/viewvc/blink?revision=159412&view=revision

BUG=306882
TEST=none because there are no easy ways to enable the password generation feature in Blink

Review URL: https://codereview.chromium.org/28413002

git-svn-id: svn://svn.chromium.org/blink/trunk@159985 bbb929c8-8fbe-4397-9dbb-9b2b20218538