Remove unused Platform functions sandboxEnabled() and availableDiskSpaceInBytes()
Remove unused Platform functions sandboxEnabled() and availableDiskSpaceInBytes()

These are unused and don't make a lot of sense to expose to Blink.

R=abarth

Review URL: https://chromiumcodereview.appspot.com/16599009

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@152241 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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