Avoids minimizing docked window in a unit test.
When investigating https://codereview.chromium.org/173443002, sadrul@ noticed that the first window gets minimized after a second window is docked (because there is not enough vertical space). Updated the screen size for this test to ensure it doesn't happen as well as updating the test to explicitly verify that the state is not minimized.

BUG=none

Review URL: https://codereview.chromium.org/173843003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252340 0039d316-1c4b-4281-b951-d872f2087c98
Volume button now controls media volume for WebAudio.

Today, WebAudio uses the OpenSL ES low-latency audio backend in media/audio but the stream type is always communication mode (which is OK for WebRTC but not for WebAudio).

This patch ensures that:

- Only switch to system-wide Communication mode when a low-latency input stream is created (e.g. from getUserMedia).
- Opens the native output stream in Media mode if system mode is Media and in Communication mode if system mode is Communication.

To summarize: an application which renders WebAudio audio should now be able to see the default media volume icon and change the volume accordingly.

TEST=http://chromium.googlecode.com/svn/trunk/samples/audio/shiny-drum-machine.html
BUG=342114

Review URL: https://codereview.chromium.org/173503003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252341 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252341
Move ContextFactory setup out of AuraTestHelper.

Some users of the test helper want to use ImageTransportFactory, which
also sets up a ContextFactory, meaning we end up setting up 2
ContextFactories currently for those tests. A DCHECK() added to
ContextFactory::SetInstance() caught this. So I've moved the
ContextFactory setup from AuraTestHelper to each of its owners.

While doing so, the the |allow_test_contexts| flag has been inverted
to |enable_pixel_output| since we'll be removing the concept of
test compositor/contexts from these tests.

R=piman@chromium.org
TBR=ben@chromium.org, piman@chromium.org
BUG=270918

Review URL: https://codereview.chromium.org/173113002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252342 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252342