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Current HeadUpDisplayLayerImpl allocates one resource
and reuse it continuously. This patch is trying to
allocate two resources and swap one of them
which is available.
so HeadUpDisplayLayerImpl does not need free the resource
while the layer is alive.

Bug=None

Review URL: https://codereview.chromium.org/491783003

Cr-Commit-Position: refs/heads/master@{#292690}