Add Chrome OS accessibility histograms.

chrome/browser/chromeos/accessibility/accessibility_util.h

Index: chrome/browser/chromeos/accessibility/accessibility_util.h
diff --git a/chrome/browser/chromeos/accessibility/accessibility_util.h b/chrome/browser/chromeos/accessibility/accessibility_util.h
index c264dbc71986accd7ddbdb533733c12936e01f56..fe99b33b5dbca1aaf98f2cab3f42ee2db338c291 100644
--- a/chrome/browser/chromeos/accessibility/accessibility_util.h
+++ b/chrome/browser/chromeos/accessibility/accessibility_util.h
@@ -18,6 +18,9 @@ class WebUI;
 namespace chromeos {
 namespace accessibility {
 
+// Do any accessibility initialization that should happen once on startup.
+void Initialize();
+
 // Enables or disables spoken feedback. Enabling spoken feedback installs the
 // ChromeVox component extension.  If this is being called in a login/oobe
 // login screen, pass the WebUI object in login_web_ui so that ChromeVox
@@ -46,6 +49,9 @@ bool IsSpokenFeedbackEnabled();
 // Returns true if High Contrast is enabled, or false if not.
 bool IsHighContrastEnabled();
 
+// Returns true if the Virtual Keyboard is enabled, or false if not.
+bool IsVirtualKeyboardEnabled();
+
 // Returns the current state of the screen magnifier.
 ash::MagnifierType GetMagnifierType();