Measure DOMStringList::contains() usage

There's a desire to remove DOMStringList from the platform, in favor
of just returning JS Array objects, but Array doesn't have a
contains() method. Measure the usage, to see if this is feasible.

BUG=350146
R=abarth

Review URL: https://codereview.chromium.org/189473002

git-svn-id: svn://svn.chromium.org/blink/trunk@168768 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Turn SVGTextMetricsBuilder into a namespace

Said class does not carry any state, so turn it into a namespace, marking
previous methods static as appropriate and modify callers.

Review URL: https://codereview.chromium.org/191053002

git-svn-id: svn://svn.chromium.org/blink/trunk@168769 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Split out non-loader related callbacks into FrameClient.

When the frame tree was moved into Source/web, the bridge functions were
placed on FrameLoaderClient since that was the simplest thing to do at
the time. It no longer makes sense to keep them there, since
RemoteFrames will not have a FrameLoaderClient but they still need to be
able to access this information.

BUG=346764

Review URL: https://codereview.chromium.org/189633002

git-svn-id: svn://svn.chromium.org/blink/trunk@168770 bbb929c8-8fbe-4397-9dbb-9b2b20218538