Expose channel-associated interfaces to blink.

Move AssociatedInterface{Provider,Registry} into blink/common so blink
can use them. Add an accessor in LocalFrame to provide access to the
RenderFrame's AssociatedInterfaceProvider.

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_site_isolation
Change-Id: I412f3b559a9777609b2998206970f5c16d43f0c4
Tbr: [email protected]
Reviewed-on: https://chromium-review.googlesource.com/706740
Commit-Queue: Sam McNally <[email protected]>
Reviewed-by: Kinuko Yasuda <[email protected]>
Reviewed-by: Ken Rockot <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Cr-Commit-Position: refs/heads/master@{#519937}
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index d939aaa..a2372b67 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -2162,7 +2162,7 @@
       &params));
 }
 
-AssociatedInterfaceRegistry*
+blink::AssociatedInterfaceRegistry*
 RenderThreadImpl::GetAssociatedInterfaceRegistry() {
   return &associated_interfaces_;
 }