Remove #if ENABLE(NAVIGATOR_CONTENT_UTILS) from blink

r163413 and r239691 have supported a runtime enable flag for the navigator content utils.
So, ENABLE(NAVIGATOR_CONTENT_UTILS) doesn't need to be exist anymore.

BUG=N/A

Review URL: https://codereview.chromium.org/110183002

git-svn-id: svn://svn.chromium.org/blink/trunk@164486 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IDL compiler: sync Python to r164451

Python side to:
Remove raw DOM templates from V8 bindings
https://codereview.chromium.org/104873018

BUG=239771
TBR=haraken
NOTRY=true

Review URL: https://codereview.chromium.org/113863004

git-svn-id: svn://svn.chromium.org/blink/trunk@164487 bbb929c8-8fbe-4397-9dbb-9b2b20218538