Allow external applications to register for mojo: urls

Allow external applications to register for mojo: urls

BUG=
R=aa@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/0504d06d6fad0c811a8880d07dc58faf7450f641

[DaveMoore, 2015-01-21 18:34:22]

Cleanup

[DaveMoore, 2015-01-21 18:34:50]

davemoore@chromium.org changed reviewers:
+ aa@google.com

[DaveMoore, 2015-01-22 20:34:06]

davemoore@chromium.org changed reviewers:
+ aa@chromium.org
- aa@google.com

[Aaron Boodman, 2015-01-22 20:52:42]

I think this could be simplified relatively easily, but I don't know if it makes
sense to do as part of this CL or not.

It seems like ResolveMappings() and ResolveURL() could be combined, since they
are just different kinds of URL mapping.

Then Connect...() calls them in a loop trying to find an existing connection,
then a loader at each step.

Once Resolve() returns the same URL, then Connect finally uses the default
loader.

https://codereview.chromium.org/861293002/diff/20001/shell/application_manage...
File shell/application_manager/application_manager.h (right):

https://codereview.chromium.org/861293002/diff/20001/shell/application_manage...
shell/application_manager/application_manager.h:119: ShellImpl*
GetShellImpl(const GURL& url);
append("\n")

[Aaron Boodman, 2015-01-22 21:45:31]

lgtm in case you want to land this now

[DaveMoore, 2015-01-23 23:30:42]

Merge / nits

[DaveMoore, 2015-01-23 23:33:33]

Committed patchset #3 (id:40001) manually as
0504d06d6fad0c811a8880d07dc58faf7450f641 (presubmit successful).