Check WindowDelegate in the methods which assume the target has the delegate.

BUG=338787
R=sadrul@chromium.org

Review URL: https://codereview.chromium.org/149063003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247570 0039d316-1c4b-4281-b951-d872f2087c98
android envsetup: Remove default_target=All

If targets shouldn't be part of the android build, they should be conditional
in gyp instead.

Removing this line leads to 17 more files being compiled and one more binary
(printing_unittests) being linked on the open source bots, and there are no
build errors.

(An internal build of the 'all' target is also successful, and it builds only
183 additional edges too, which add about 1 minute / 5% to build time.)

BUG=330631
NOTRY=true

Review URL: https://codereview.chromium.org/149103002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247571 0039d316-1c4b-4281-b951-d872f2087c98
Linux: tear down Zygote at browser shutdown.

In BrowserMainLoop::ShutdownThreadsAndCleanUp(), we explicitly call
a new ZygoteHostImpl::TearDownAfterLastChild API to notify the Zygote
to exit after its last child died.

The notification is to simply close the IPC channel to the Zygote.
Before this patch, this would happen implicitly when the browser process
died.

To implement this, we add a lightweight child tracking mechanism to ZygoteHostImpl.

BUG=334345
R=piman@chromium.org

Review URL: https://codereview.chromium.org/148443006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247572 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247572