Removing iTunes support from media_gallery API.

Removing iTunes support from media_gallery API on Windows and Mac, as it is
not maintained and has been broken on Windows since iTunes changed its
configuration file locations more than a year ago.

Bug: 762991,758355
Tbr: tsepez, bbudge
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_dbg_ng
Change-Id: I258659e5241f27f5ad2b0cc86ba8f902f77a32e7
Reviewed-on: https://chromium-review.googlesource.com/646801
Commit-Queue: Jay Civelli <[email protected]>
Reviewed-by: Michael Nordman <[email protected]>
Reviewed-by: Lei Zhang <[email protected]>
Reviewed-by: Istiaque Ahmed <[email protected]>
Reviewed-by: Tommy Li <[email protected]>
Cr-Commit-Position: refs/heads/master@{#500748}
59 files changed