Provide default implementations for WebLayer functions that will soon be removed.
Provide default implementations for WebLayer functions that will soon be removed.

The WebLayer functions setMaxScrollPosition() and setScrollable() will be
going away after https://codereview.chromium.org/23983047 lands, so we need
a default implementation in the meantime.

BUG=

Review URL: https://codereview.chromium.org/139523002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@165180 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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