Lots of code attempts to move url::Origin objects. Unfortunately, whilst
Origins had an implicitly-declared copy constructor, they did not have
an implicitly-declared move constructor since the user-declared
destructor prevents that. Attempting to move Origin objects compiled
fine however, since it was just falling through to the copy constructor.

This code adds a default move constructor & move assignment operator
to Origin and SchemeHostPort, so that they will be moved instead of
copied when possible. Existing code should become faster :)

(The patch also adds a default copy constructor & copy assignment
operator, since otherwise adding the user-defined move constructor would
cause the implicit ones to be deleted).

Bug: none
Change-Id: Ic250f3c8172c75a386294053719cc1ceb82bbdf5
Reviewed-on: https://chromium-review.googlesource.com/692022


Reviewed-by: Mike West <mkwst@chromium.org>
Commit-Queue: John Mellor <johnme@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506366}