Show ChromeVox caption panel when spoken feedback is enabled.

ash/shelf/shelf_layout_manager.h

Index: ash/shelf/shelf_layout_manager.h
diff --git a/ash/shelf/shelf_layout_manager.h b/ash/shelf/shelf_layout_manager.h
index 8b5d166a1ef5d03843d9b5612ba9635a008af453..f2dcf0fac974d4269abcdd30be716d318c7f4b08 100644
--- a/ash/shelf/shelf_layout_manager.h
+++ b/ash/shelf/shelf_layout_manager.h
@@ -215,6 +215,9 @@ class ASH_EXPORT ShelfLayoutManager
   // Is the shelf's alignment horizontal?
   bool IsHorizontalAlignment() const;
 
+  // Get the work area insets due to the shelf and virtual keyboard.
+  gfx::Insets GetWorkAreaInsets() const;
+
   // Returns a ShelfLayoutManager on the display which has a shelf for
   // given |window|. See RootWindowController::ForShelf for more info.
   static ShelfLayoutManager* ForShelf(aura::Window* window);
@@ -412,6 +415,10 @@ class ASH_EXPORT ShelfLayoutManager
   // keyboard.
   gfx::Rect user_work_area_bounds_;
 
+  // The insets from the sides of the screen taken up by the shelf or virtual
+  // keyboard.
+  gfx::Insets work_area_insets_;
+
   // The show hide animation duration override or 0 for default.
   int duration_override_in_ms_;