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

athena/wm/split_view_controller.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ATHENA_WM_SPLIT_VIEW_CONTROLLER_H_
 #define ATHENA_WM_SPLIT_VIEW_CONTROLLER_H_
 
 #include "athena/athena_export.h"
 #include "athena/wm/bezel_controller.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 17 matching lines @@
 
   virtual ~SplitViewController();
 
   bool IsSplitViewModeActive() const;
 
   // Activates split-view mode with |left| and |right| windows. If |left| and/or
   // |right| is NULL, then the first window in the window-list (which is neither
   // |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@

                      aura::Window* replace_with);
 
   // Returns the bounds that the left and right windows will have once split
   // view is active and they are done animating. If |left_window_| and
   // |right_window_| are still animating this may be different than their
   // current bounds.
   gfx::Rect GetLeftTargetBounds();
   gfx::Rect GetRightTargetBounds();
 
   aura::Window* left_window() { return left_window_; }
   aura::Window* right_window() { return right_window_; }
 
  private:
   enum State {
     // Split View mode is not active. |left_window_| and |right_window| are
     // NULL.
     INACTIVE,
     // Two windows |left_window_| and |right_window| are shown side by side and
     // there is a horizontal scroll in progress which is dragging the separator
     // between the two windows.
     SCROLLING,
     // Split View mode is active with |left_window_| and |right_window| showing
     // side by side each occupying half the screen. No scroll in progress.
     ACTIVE
   };
 
   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);
 
   // BezelController::ScrollDelegate:
   virtual void ScrollBegin(BezelController::Bezel bezel, float delta) OVERRIDE;
   virtual void ScrollEnd() OVERRIDE;
   virtual void ScrollUpdate(float delta) OVERRIDE;
   virtual bool CanScroll() OVERRIDE;
 
   State state_;
@@ skipping 13 matching lines @@
   int separator_position_;
 
   base::WeakPtrFactory<SplitViewController> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SplitViewController);
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_WM_SPLIT_VIEW_CONTROLLER_H_