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Now that the updates to the blink side have been pushed through, we can use
ActivityLog with previous values for setters and for hrefs of anchor tags.
Add the logic to do so and update tests.

BUG=357204

Review URL: https://codereview.chromium.org/270623005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270752 0039d316-1c4b-4281-b951-d872f2087c98