Simplify CustomElementHelpers and rename it CustomElementWrapper.

All this class does is wrap Custom Elements, and its only callers are
V8(HTML|SVG)ElementWrapperFactory. Rename it and make its API a
private club.

BUG=234509

Review URL: https://chromiumcodereview.appspot.com/18825002

git-svn-id: svn://svn.chromium.org/blink/trunk@153713 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove mediastream and mediasource dependncies from DOMURL

This change extracs module dependent part of DOMURL into
partial interfaces so that DOMURL doesn't have direct
dependency to these modules.

BUG=240988
TEST=none
R=abarth,tkent

Review URL: https://chromiumcodereview.appspot.com/18162007

git-svn-id: svn://svn.chromium.org/blink/trunk@153714 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix display of WTF::Vectors in gdb.

WTF::Vector now inherits from VectorBufferBase instead of containing it as an
m_buffer member.

R=tony@chromium.org

Review URL: https://codereview.chromium.org/18337009

git-svn-id: svn://svn.chromium.org/blink/trunk@153715 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make BaselineOptimizer virtual test suite aware.

With this patch, we'll optimize the virtual subtree, then see if we can
remove the virtual root baseline and then optimize the non-virtual subtree.

The new code and tests are kind of messy, but I didn't see a cleaner way to
do it. A lot of the mess comes from the fact the the virtual/* is both
in the directory name and in the baseline name.

BUG=237701
R=abarth@chromium.org

Review URL: https://codereview.chromium.org/18603012

git-svn-id: svn://svn.chromium.org/blink/trunk@153716 bbb929c8-8fbe-4397-9dbb-9b2b20218538