[v8] Allow WebAssembly.compileStreaming on workers

WebAssembly.compileStreaming should work both on the main thread as well
as on workers. However, we did not register the callback which is
required for WebAssembly.compileStreaming on the isolate of workers.
With this CL we move the registration of the callback to the
V8Initializer, where I think it belongs, and then register it both for
the isolate of the main thread as well as for the isolate of the
workers.

To make this possible I moved the WasmResponseExtensions implementation
from bindings/modules/... to bindings/core/... Please let me know if
there is a better way to do it, I'm not too much familiar with the
abstractions on the chrome side.

R=haraken@chromium.org

Bug: chromium:808707
Change-Id: I35fa55a8c83feebbc93f66fe85fc0580cb343068
Reviewed-on: https://chromium-review.googlesource.com/908848
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#535707}
8 files changed