Add window states docked; and docked minimized. Add wm window event to set docked and undocked.

ash/wm/dock/docked_window_layout_manager.h

Index: ash/wm/dock/docked_window_layout_manager.h
diff --git a/ash/wm/dock/docked_window_layout_manager.h b/ash/wm/dock/docked_window_layout_manager.h
index 51b302ec3cf0bfeab47e1605d50dc4e2a953afd5..988fa03617504933e668c4fdeaa41370395987c9 100644
--- a/ash/wm/dock/docked_window_layout_manager.h
+++ b/ash/wm/dock/docked_window_layout_manager.h
@@ -107,6 +107,11 @@ class ASH_EXPORT DockedWindowLayoutManager
   // Records |action| by |source| in UMA.
   void FinishDragging(DockedAction action, DockedActionSource source);
 
+  // Request the desired dock alignment. The alginment adjustment may not
+  // be applied as it may not be available; for example if the shelf
+  // is in the requested place; the transformation won't be applied.
+  void RequestDesiredDockedAlignment(DockedAlignment desired_alignment);

[varkha, 2014/09/30 20:15:21]

From the comment sounds like MaybeSetDesiredDockedAlignment. The comments are
usually written describing what the method does ("Sets...", "Allocates...",
"Calculates...", etc). So in this case it could be "Checks the rules and
possibly updates the docked layout to conform to |desired_alignment|. May not
apply the |desired_alignment| when current shelf alignment conflicts with it.
Never clears the |alignment_|."

[dtapuska, 2014/10/01 15:01:34]

Done.

+
   Shelf* shelf() { return shelf_; }
   void SetShelf(Shelf* shelf);
 
@@ -183,6 +188,16 @@ class ASH_EXPORT DockedWindowLayoutManager
   // Ideal (starting) width of the dock.
   static const int kIdealWidth;
 
+  // Calculate the alignment of the dock; the children need to be traversed;
+  // and the |child| should be skipped in the calculation. The computed dock
+  // alignment is returned.
+  DockedAlignment CalculateDockedAlignmentExcept(const aura::Window* child)

[varkha, 2014/09/30 20:15:19]

nit: How about CalculateAlignmentExcept?
nit: Calculates...
nit: Avoid passive (e.g. "Returns alignment of docked windows other than the
|child|.")

[dtapuska, 2014/10/01 15:01:34]

Done.

+      const;
+
+  // Determine if the |desired_alignment| is applicable taking into account

[varkha, 2014/09/30 20:15:21]

I think this is IsDockedAlignmentValid.
nits:
s/desired_alignment/alignment
s/Determine/Determines.
s/location of the shelf/shelf alignment.

[dtapuska, 2014/10/01 15:01:34]

Done.

+  // the location of the shelf.
+  bool IsDockedAlignmentApplicable(DockedAlignment desired_alignment) const;
+
   // Keep at most kMaxVisibleWindows visible in the dock and minimize the rest
   // (except for |child|).
   void MaybeMinimizeChildrenExcept(aura::Window* child);