Remove unused |context| from GetDefaultParent().

ash/common/wm/container_finder.h

Index: ash/common/wm/container_finder.h
diff --git a/ash/common/wm/container_finder.h b/ash/common/wm/container_finder.h
index 25570b516988f89f8fa8eeec1d41210f2c0e88e0..f14733108a003c0fd60ed5f7b34b71772dd72635 100644
--- a/ash/common/wm/container_finder.h
+++ b/ash/common/wm/container_finder.h
@@ -26,11 +26,9 @@ namespace wm {
 // Returns the first ancestor of |window| that has a known container ID.
 ASH_EXPORT WmWindow* GetContainerForWindow(WmWindow* window);
 
-// Returns the parent to add |window| to in |context|. This is generally
-// used when a window is moved from one root to another. In this case |context|
-// is the new root to add |window| to.
-ASH_EXPORT WmWindow* GetDefaultParent(WmWindow* context,
-                                      WmWindow* window,
+// Returns the parent to add |window| to. This is generally used when a window
+// is moved from one root to another.
+ASH_EXPORT WmWindow* GetDefaultParent(WmWindow* window,
                                       const gfx::Rect& bounds);
 
 // Returns the list of containers that match |container_id| in all root windows.