Revert of [Sync] Move //components/sync to the syncer namespace. (patchset #5 id:40001 of https://codereview.chromium.org/2376123003 )

Reason for revert:
Speculative revert for components_unittests failures on debug builds, https://crbug.com/652136.

Original issue's description:
> [Sync] Move //components/sync to the syncer namespace.
>
> Things in components should live in namespaces that match their
> component. Unfortunately "sync" is a symbol defined in the std library,
> so in this case we are using "syncer".
>
> This CL does the following things inside //components/sync:
>
> - Replaces all uses of syncer_v2, sync_driver, sync_driver_v2, and browser_sync with syncer.
> - Adds syncer namespace to some classes that were missing a namespace.
> - Removes almost all "syncer::" prefixes since they became redundant.
>
> Everything outside the component is just fixing namespace prefixes and forward declarations.
> I also fixed *some* lints, especially in headers outside of the component.
>
> This script was the starting point for this CL: http://pastebin.com/PPhPTtRK
>
> BUG=646685
> TBR=caitkp
>
> Committed: https://crrev.com/a1a854356c262a2e501dc3f30ea93585f1c8635a
> Cr-Commit-Position: refs/heads/master@{#422239}

TBR=maxbogue@chromium.org
BUG=646685, 652136

Review-Url: https://codereview.chromium.org/2388673002
Cr-Commit-Position: refs/heads/master@{#422365}
567 files changed