Make LaunchViewerAndWaitForConnection() always result in the viewer not trying to launch a browser process back.

scottmg did the necessary plumbing to make this true for ash_unittests (via "test_open"), but it should be true for all users of this path (i.e., currently that's only ash_unittests and browser_tests --ash-browsertests).

This CL also adds the 'metro_viewer_constants' target to avoid having to depend on the 'metro_viewer' target itself in various other targets.

BUG=286205
TEST=No more pipe errors on http://build.chromium.org/p/chromium.fyi/builders/Chromium%20Win%20Aura%20Ash%20(1)

Review URL: https://codereview.chromium.org/98853005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239992 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239992
Do not allow creating dummy notifier id in production.

Somehow NotifierId() default constructor still exists but this is
really misleading, because it creates an id only for test use.
To apply this rule explicitly, move this constructor to private.

BUG=327033
R=dewittj@chromium.org
TBR=jamescook@chromium.org
TEST=no functional change, compile succeeds

Review URL: https://codereview.chromium.org/101473003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239993 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239993
aw: Increase disk cache size to 20M

Disk cache was 20M before Android Kitkat. See kMaximumCacheSizeBytes in
https://android.googlesource.com/platform/external/webkit/+/jb-mr2-release/Source/WebKit/android/WebCoreSupport/WebCache.cpp

So increase our limit to 20M as well.

BUG=323871

Review URL: https://codereview.chromium.org/111603003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239994 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239994