Deletes mojo::Callback

Removes all references to mojo::Callback and mojo::Closure,
replacing them with base::Callback or base::Closure, or
where applicable a mojom-generated callback alias.

The vast majority of the changes here are name changes only,
as mojo::Callback is already an alias for base::Callback.
Hence the TBRs.

Also removes mojo/public/cpp/bindings/callback.h

BUG=620840
[email protected] for chrome, content, misc
[email protected] for components/arc
[email protected] for media
[email protected] for third_party/WebKit

Committed: https://crrev.com/3524eb5ef75b90527195d82f8b9cf3bd2cdf04ef
Review-Url: https://codereview.chromium.org/2080513002
Cr-Original-Commit-Position: refs/heads/master@{#400616}
Cr-Commit-Position: refs/heads/master@{#400620}
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index 3c9cd7f9..6c98f733 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -671,7 +671,7 @@
 
     mojom::FrameRequest TakeFrameRequest() { return std::move(frame_request_); }
     mojom::FrameHostPtr TakeFrameHost() {
-      frame_host_.set_connection_error_handler(mojo::Closure());
+      frame_host_.set_connection_error_handler(base::Closure());
       return std::move(frame_host_);
     }