Fix crash when using title drag on a window opened while split view is active

athena/wm/split_view_controller.h

Index: athena/wm/split_view_controller.h
diff --git a/athena/wm/split_view_controller.h b/athena/wm/split_view_controller.h
index d0e70735e3899f6d892cf028048dddc985ee249e..ce28867fac1dea756f13fdf794339c0c0160fde7 100644
--- a/athena/wm/split_view_controller.h
+++ b/athena/wm/split_view_controller.h
@@ -35,9 +35,7 @@ class ATHENA_EXPORT SplitViewController
   // |left| nor |right|) is selected instead.
   void ActivateSplitMode(aura::Window* left, aura::Window* right);
 
-  // Resets the internal state to an inactive state. Calling this does not

[mfomitchev, 2014/09/02 16:23:28]

It looks like we call UpdateLayout(false), which does update the transform... 

[pkotwicz, 2014/09/02 17:54:35]

Yup

Aside: It turns out that there are two callers of DeactivateSplitMode().
WindowManagerImpl::OnSelectWindow() expects DeactivateSplitMode() to animate (or
not tamper with the current animation) and WindowManagerImpl::ToggleSplitview()
expects DeactivateSplitMode() to reset the transforms.
- The CL as is fixes a bug where the animation would do super weird things if
Ctrl+F6 was hit while exiting overview into split mode
- The CL as is prematurely hides the left and right windows when exiting
overview mode.

In a follow up CL (a fancier version of
https://codereview.chromium.org/527313002/), I will add a parameter to
DeactivateSplitMode() which indicates whether split mode should animate
deactivation.

-  // change the window bounds/transforms etc. The caller must take care of
-  // making any necessary changes.
+  // Resets the internal state to an inactive state.
   void DeactivateSplitMode();
 
   void ReplaceWindow(aura::Window* window,

[mfomitchev, 2014/09/02 16:23:28]

Would be good to document that this does a layout as well updating
bounds/transform of |replace_with| and doesn't affect the bounds of |window|.

[pkotwicz, 2014/09/02 17:54:35]

Done.

Perhaps this method should also update |window|'s bounds... That's something for
a future CL which needs to be debated with sadrul@

@@ -69,11 +67,12 @@ class ATHENA_EXPORT SplitViewController
 
   void UpdateLayout(bool animate);
 
-  void SetWindowTransform(aura::Window* left_window,
-                          const gfx::Transform& transform,
-                          bool animate);
+  void SetWindowTransforms(const gfx::Transform& left_transform,
+                           const gfx::Transform& right_transform,
+                           bool animate);
 
-  void OnAnimationCompleted(aura::Window* window);
+  // Called when the animation initiated by SetWindowTransforms() completes.
+  void OnAnimationCompleted();
 
   void UpdateSeparatorPositionFromScrollDelta(float delta);