Keep the split view activities topmost in z-order in Athena

athena/wm/split_view_controller.cc

 // 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.
 
 #include "athena/wm/split_view_controller.h"
 
 #include <cmath>
 
 #include "athena/screen/public/screen_manager.h"
 #include "athena/wm/public/window_list_provider.h"
@@ skipping 44 matching lines @@
 
 SplitViewController::~SplitViewController() {
 }
 
 bool SplitViewController::IsSplitViewModeActive() const {
   return state_ == ACTIVE;
 }
 
 void SplitViewController::ActivateSplitMode(aura::Window* left,
                                             aura::Window* right) {
+  DCHECK((left && wm::IsActiveWindow(left)) ||
+         (right && wm::IsActiveWindow(right)));
+

[sadrul, 2014/09/09 14:27:28]

We allow both to be NULL.

   aura::Window::Windows windows = window_list_provider_->GetWindowList();
   aura::Window::Windows::reverse_iterator iter = windows.rbegin();
   if (state_ == ACTIVE) {
     if (left_window_ == right)
       left_window_ = left;
     if (right_window_ == left)
       right_window_ = right;
 
     if (!left)
       left = left_window_;
@@ skipping 13 matching lines @@
   if (!right && iter != windows.rend()) {
     right = *iter;
     iter++;
     if (right == left && iter != windows.rend()) {
       right = *iter;
       iter++;
     }
   }
 
   SetState(ACTIVE);
-  if (right_window_ != right) {
-    right_window_ = right;
-    container_->StackChildAtTop(right_window_);
-  }
-  if (left_window_ != left) {
-    left_window_ = left;
-    container_->StackChildAtTop(left_window_);
-  }
+  right_window_ = right;
+  left_window_ = left;
   UpdateLayout(true);
 }
 
 void SplitViewController::ReplaceWindow(aura::Window* window,
                                         aura::Window* replace_with) {
   CHECK(IsSplitViewModeActive());
   CHECK(replace_with);
   CHECK(window == left_window_ || window == right_window_);
   CHECK(replace_with != left_window_ && replace_with != right_window_);
 #if !defined(NDEBUG)
   aura::Window::Windows windows = window_list_provider_->GetWindowList();
   DCHECK(std::find(windows.begin(), windows.end(), replace_with) !=
          windows.end());
 #endif
 
   if (window == left_window_)
     left_window_ = replace_with;
   else
     right_window_ = replace_with;
-  wm::ActivateWindow(replace_with);
   UpdateLayout(false);
   window->SetTransform(gfx::Transform());
   window->Hide();
 }
 
 void SplitViewController::DeactivateSplitMode() {
   CHECK_EQ(ACTIVE, state_);
   SetState(INACTIVE);
   UpdateLayout(false);
   left_window_ = right_window_ = NULL;
@@ skipping 32 matching lines @@
     if (!wm::IsActiveWindow(left_window_))
       left_window_->Hide();
     if (!wm::IsActiveWindow(right_window_))
       right_window_->Hide();
     SetWindowTransforms(gfx::Transform(), gfx::Transform(), false);
     return;
   }
 
   left_window_->Show();
   right_window_->Show();
+  DCHECK(wm::IsActiveWindow(left_window_) || wm::IsActiveWindow(right_window_));
+  if (wm::IsActiveWindow(left_window_))
+    container_->StackChildBelow(right_window_, left_window_);
+  else
+    container_->StackChildBelow(left_window_, right_window_);

[sadrul, 2014/09/09 14:27:27]

Can the z-ordering issue described in the bug be fixed by just this block of
change?

[pkotwicz, 2014/09/09 17:06:28]

The remainder of the change is to ensure that either |left_window_| or
|right_window_| is active. That's the reason why I have changed
ActivateSplitMode() such that one of its arguments must be the active window
(and ActivateSplitMode() cannot be called with two NULL arguments)

[sadrul, 2014/09/11 05:45:48]

We are still activating windows from various places after this change. I do not
think this is an improvement over the current state. Can we just do
StackChildAtTop(left), StackChildAtTop(right) here?

+
   if (state_ == ACTIVE) {
     if (animate) {
       gfx::Transform left_transform = GetTargetTransformForBoundsAnimation(
           left_window_->bounds(), GetLeftTargetBounds());
       gfx::Transform right_transform = GetTargetTransformForBoundsAnimation(
           right_window_->bounds(), GetRightTargetBounds());
       SetWindowTransforms(left_transform, right_transform, true);
     } else {
       left_window_->SetBounds(GetLeftTargetBounds());
       right_window_->SetBounds(GetRightTargetBounds());
@@ skipping 124 matching lines @@
 bool SplitViewController::CanScroll() {
   // TODO(mfomitchev): return false in full screen.
   bool result = (!IsSplitViewModeActive() &&
                  window_list_provider_->GetWindowList().size() >= 2 &&
                  IsLandscapeOrientation(gfx::Screen::GetNativeScreen()->
                      GetDisplayNearestWindow(container_).rotation()));
   return result;
 }
 
 }  // namespace athena