This patch improves setStyleSheetText command so that it is able to
set text for the stylesheets, generated for "style"
attribute.

BUG=341506

Review URL: https://codereview.chromium.org/132803013

git-svn-id: svn://svn.chromium.org/blink/trunk@167008 bbb929c8-8fbe-4397-9dbb-9b2b20218538