Remove the ENABLE_LINK_PRERENDER compile-time flag.

This shouldn't have any web-visible effect, as Chromium never disables the
feature; we love prerendering!

Review URL: https://codereview.chromium.org/13881009

git-svn-id: svn://svn.chromium.org/blink/trunk@148368 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove the ENABLE_XSLT compile-time flag.

This mostly mechanical patch shouldn't have any web-visible effect; XSLT has
been enabled for quite some time. The only non-mechanical bits of this patch
are the drive-by additions of "// namespace WebCore" to the closing braces
of a few XSLT files that I noticed while dropping "#endif" statements.

Review URL: https://codereview.chromium.org/14113007

git-svn-id: svn://svn.chromium.org/blink/trunk@148369 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add experimentalShadowDOMEnabled runtime flag.

Since shadowDOMEnabled is enabled by default, we are planning:
(1) adding experimentalShadowDOMEnabled runtime flag to guard experimental features,
(2) making non-experimental shadow dom codes always available (i.e. removing "if(shadowDOMEnabled())"),
(3) finally, changing chrome://flags to use experimentalShadowDOMEnabled, and removing shadowDOMEnabled runtime flag.

This patch is for (1).

BUG=

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=148349

Review URL: https://codereview.chromium.org/14009003

git-svn-id: svn://svn.chromium.org/blink/trunk@148370 bbb929c8-8fbe-4397-9dbb-9b2b20218538