A11y: Add the option to always show the a11y tray menu regardless of the state of a11y features

Change summary:
- Add 'const' to ShellDelegate::IsUserLoggedIn()
- Use TrayImageItem::UpdateAfterLoginStatusChange delegate instead of ShellObserver::OnLoginStateChanged()
- Add a pref: kShouldAlwaysShowAccessibilityMenu
- Add a checkbox to chrome://settings

BUG=158287
TEST=manual

Review URL: https://chromiumcodereview.appspot.com/11280236

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@170732 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 4 insertions, 4 deletions

diff --git a/ash/shell_delegate.h b/ash/shell_delegate.h
index 2b067d745..a7eb838 100644
--- a/ash/shell_delegate.h
+++ b/ash/shell_delegate.h
@@ -67,19 +67,19 @@ class ASH_EXPORT ShellDelegate {
   virtual ~ShellDelegate() {}
 
   // Returns true if user has logged in.
-  virtual bool IsUserLoggedIn() = 0;
+  virtual bool IsUserLoggedIn() const = 0;
 
   // Returns true if we're logged in and browser has been started
-  virtual bool IsSessionStarted() = 0;
+  virtual bool IsSessionStarted() const = 0;
 
   // Returns true if this is the first time that the shell has been run after
   // the system has booted.  false is returned after the shell has been
   // restarted, typically due to logging in as a guest or logging out.
-  virtual bool IsFirstRunAfterBoot() = 0;
+  virtual bool IsFirstRunAfterBoot() const = 0;
 
   // Returns true if a user is logged in whose session can be locked (i.e. the
   // user has a password with which to unlock the session).
-  virtual bool CanLockScreen() = 0;
+  virtual bool CanLockScreen() const = 0;
 
   // Invoked when a user locks the screen.
   virtual void LockScreen() = 0;