Refactored the DeviceManagementService to get its parameters from a delegate.

The DeviceManagementService will be moved along with the policy/ code into a new
component, and thus it can't access //chrome nor //chromeos code. A recent
refactoring in that direction introduced a regression because it called
StatisticsProvider::GetMachineStatistic() before the StatisticsProvider was
initialized.

This used to work before because GetMachineStatistic() was called only once the
first request was sent to the server (which, on enrolled devices, happens in
a task that is immediately posted but the StatisticsProvider is already
initialized by then).

This change introduces a delegate that the DeviceManagementService uses to
get its configuration parameters, so that the call to GetMachineStatistic()
can again be performed only when a request is sent.

BUG=271392,302798

Review URL: https://codereview.chromium.org/25690003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226499 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226499
Blink roll 158674:158697

http://build.chromium.org/f/chromium/perf/dashboard/ui/changelog_blink.html?url=/trunk&range=158675:158697&mode=html
TBR=
BUG=

Review URL: https://codereview.chromium.org/25638004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226500 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226501 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226500
aura: Use Layer::SetShowPaintedContent to stop showing external content

Currently we use SetExternalTexture(NULL) or SetDelegatedFrame(NULL)
to switch back to showing painted content. This is kinda indirect,
and won't play nicely when SetExternalTexture() is removed, and when
we use a FrameProvider for delegated frames instead of pushing them
to the ui::Layer directly one at a time.

Instead, add SetShowPaintedContent() to switch to a content layer,
and disallow setting a NULL/empty texture or delegated frame.

Also View::SetExternalTexture() is not used, remove it so it doesn't
have to think about this change.

R=piman,sadrul
BUG=263069

Review URL: https://codereview.chromium.org/25596002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226502 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226502