Expose replacesCurrentHistoryItem() on WebDataSource.

Currently, there is a WebDataSource::isClientRedirect(), but it actually returns
whether or not the back forward list should be locked for the current load.
Start the process of clarify the two.

BUG=261374

Review URL: https://chromiumcodereview.appspot.com/19675005

git-svn-id: svn://svn.chromium.org/blink/trunk@154503 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Clean up isolate argument in throw error.

Remove some optional isolate = 0 which are not being used.

throwError(v8::Handle<v8::Value>) does not need an isolate. So remove
param where possible.

BUG=None

Review URL: https://chromiumcodereview.appspot.com/19517004

git-svn-id: svn://svn.chromium.org/blink/trunk@154504 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Ignore text-shadow when printing.

This undoes an accidental change in behaviour earlier on. It's not clear
what the "right" behaviour here is, but this is the simplest way to
avoid the regression in question.

BUG=258321

Review URL: https://chromiumcodereview.appspot.com/19424002

git-svn-id: svn://svn.chromium.org/blink/trunk@154505 bbb929c8-8fbe-4397-9dbb-9b2b20218538
lastHyphenLocation shouldn't require bloatedCharacters

Rather than bloating characters to create a UChar* and passing that array to
Chromium, I've taught Chromium how to receive a WebString in
https://codereview.chromium.org/19646004. That means we can use substring here
without doing extra work.

R=eseidel
BUG=254708

Review URL: https://chromiumcodereview.appspot.com/19652005

git-svn-id: svn://svn.chromium.org/blink/trunk@154506 bbb929c8-8fbe-4397-9dbb-9b2b20218538