chromeos: Make CheckIdleStateIsLocked() query D-Bus client.

Make the Chrome OS implementation of
CheckIdleStateIsLocked() (used by the chrome.idle API) get
the lock state from chromeos::SessionManagerClient instead
of depending on ash::SessionStateDelegate (which reaches
into chrome/browser/chromeos/login/). This makes it possible
for the idle code to be later moved under ui/base/ instead
of living in chrome/browser/, permitting the chrome.idle API
to be moved from chrome/ to extensions/.

As part of this, make SessionManagerClient cache the
most-recently-received-from-session_manager screen-lock
state. Previously it just passed state updates to its
observers, but the idle functions lack a class that can
register itself as an observer.

BUG=446320

Review URL: https://codereview.chromium.org/852453005

Cr-Commit-Position: refs/heads/master@{#311333}

1 files changed, 1 insertions, 0 deletions

diff --git a/chromeos/dbus/fake_session_manager_client.h b/chromeos/dbus/fake_session_manager_client.h
index c0e53aa..3d11691 100644
--- a/chromeos/dbus/fake_session_manager_client.h
+++ b/chromeos/dbus/fake_session_manager_client.h
@@ -29,6 +29,7 @@ class FakeSessionManagerClient : public SessionManagerClient {
   virtual void AddObserver(Observer* observer) override;
   virtual void RemoveObserver(Observer* observer) override;
   virtual bool HasObserver(const Observer* observer) const override;
+  virtual bool IsScreenLocked() const override;
   virtual void EmitLoginPromptVisible() override;
   virtual void RestartJob(int pid, const std::string& command_line) override;
   virtual void StartSession(const std::string& user_email) override;