Consume Mojo services directly in Blink's WebUSB implementation.

This patch takes advantage of the ability to consume a Mojo service
directly in //third_party/WebKit/Source/modules to remove the
//third_party/WebKit/public/platform/modules/webusb,
//content/renderer/usb and the rest of that intermediate layer.

BUG=None

Review URL: https://codereview.chromium.org/1850023002

Cr-Commit-Position: refs/heads/master@{#388571}
48 files changed