Use a multiset rather than a set to store bookmarks when running the model associator merge.
Use a multiset rather than a set to store bookmarks when running the model associator merge.

For cases where there's an exact duplicate URL and title,
this allows each BookmarkNode a chance to be associated
with a sync node.  With a set, we'd forget about all
but one of the duplicates, resulting in the creation
of yet more duplicates.  The result was exponential
growth with each merge and sync.

BUG=24995
TEST=

Review URL: http://codereview.chromium.org/288001

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@29307 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser