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Generating the Storage ID requires a browser specific value. Update the GN
files so that other embedders can provide the value through GN args.

Also updates the build files to reference the internal file used by Chrome
to provide the value when building official versions.

BUG=478960
TEST=compiles with changed GN args

Change-Id: Id14e32fb38c60e4d4112ab71500a98b79e3a6035
Reviewed-on: https://chromium-review.googlesource.com/812567
Commit-Queue: John Rummell <jrummell@chromium.org>
Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#525239}