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This can happen if you create a new UI resource (through LTH)
which queues a request while there are any evicted resources
(as tracked by LTHImpl).

RecreateUIResources() will then iterate over all existing client
ids and queue another CREATE request.

Simply check for duplicates before queuing more requests.

The double-upload behavior didn't play well with Android's
Thumbnail class which drops the bitmap after every
UIResourceClient::GetBitmap() call.

BUG=636630
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2247573002
Cr-Commit-Position: refs/heads/master@{#414785}