Move a window if the sceren bounds being set is in other display.

ash/display/screen_position_controller.cc

Index: ash/display/screen_position_controller.cc
diff --git a/ash/display/screen_position_controller.cc b/ash/display/screen_position_controller.cc
index 3c464b407d126fb6d884a48e620af7cb47c53e20..4ac525d0d6b3c34a40fe3f59f81260aebb3e8c64 100644
--- a/ash/display/screen_position_controller.cc
+++ b/ash/display/screen_position_controller.cc
@@ -5,13 +5,49 @@
 #include "ash/display/screen_position_controller.h"
 
 #include "ash/display/display_controller.h"
+#include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/window_properties.h"
+#include "ui/aura/client/activation_client.h"
+#include "ui/aura/client/capture_client.h"
+#include "ui/aura/client/stacking_client.h"
+#include "ui/aura/focus_manager.h"
 #include "ui/aura/root_window.h"
+#include "ui/aura/window_tracker.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/screen.h"
 
 namespace ash {
+namespace {
+
+// Move all transient children to |dst_root|, including the ones in
+// the child windows and transient children of the transient children.
+void MoveAllTransientChildToNewRoot(aura::RootWindow* dst_root,

[sky, 2012/07/20 15:06:07]

Child->Children or MoveAllTransientsToNewRoot

[oshima, 2012/07/20 17:03:11]

Done.

+                                    aura::Window* window) {
+  aura::Window::Windows transient_children = window->transient_children();
+  for (aura::Window::Windows::iterator iter = transient_children.begin();

[sky, 2012/07/20 15:06:07]

I'm worried that all this moving might have side effects and change around
transient children. Similar concern for children below.

[oshima, 2012/07/20 17:03:11]

I do too, but transient children needs to be in the same root. Do you have good
suggestion? I just couldn't think of any and thought our best bet is to fix
such issues case by case basis.

That's being said, I do think creating a root windows per display
makes aura/ash way complicated. This is necessary right now
(due to X's and current compositor's architecture), but I have
some idea that may be able to fix this, and am hoping that I can
work on it later this year.

+       iter != transient_children.end(); ++iter) {
+    aura::Window* transient_child = *iter;
+    int container_id = transient_child->parent()->id();
+    DCHECK_GE(container_id, 0);
+    aura::Window* container = Shell::GetContainer(dst_root, container_id);
+    gfx::Rect parent_bounds_in_screen = transient_child->GetBoundsInScreen();
+    container->AddChild(transient_child);
+    transient_child->SetBoundsInScreen(parent_bounds_in_screen);
+
+    // Transient children may have transient children.
+    MoveAllTransientChildToNewRoot(dst_root,
+                                   transient_child);
+  }
+  // Move transient children of the child wnidows if any.

[sky, 2012/07/20 15:06:07]

wnidows -> windows

[oshima, 2012/07/20 17:03:11]

Done.

+  aura::Window::Windows children = window->children();
+  for (aura::Window::Windows::iterator iter = children.begin();
+       iter != children.end(); ++iter)
+    MoveAllTransientChildToNewRoot(dst_root, *iter);
+}
+
+}  // namespace
+
 namespace internal {
 
 void ScreenPositionController::ConvertPointToScreen(
@@ -48,9 +84,44 @@ void ScreenPositionController::SetBounds(
     window->SetBounds(bounds);
     return;
   }
-  // TODO(oshima): Pick the new root window that most closely shares
-  // the bounds.  For a new widget, NativeWidgetAura picks the right
-  // root window.
+
+  // Don't move a transient windows to other root window.
+  // It moves when its transient_parent moves.
+  if (!window->transient_parent()) {
+    aura::RootWindow* dst_root = Shell::GetRootWindowMatching(bounds);
+    aura::Window* suggested_container = NULL;

[sky, 2012/07/20 15:06:07]

suggested_container -> dest_container

[oshima, 2012/07/20 17:03:11]

Done.

+    if (dst_root != window->GetRootWindow()) {
+      int container_id = window->parent()->id();
+      // All containers that uses screen coordinates must have non zero
+      // id.
+      DCHECK_GE(container_id, 0);

[sky, 2012/07/20 15:06:07]

DCHECK_GT

[oshima, 2012/07/20 17:03:11]

Sorry, comment was wrong. 0 is valid container id. Updated the comment.

+      suggested_container = Shell::GetContainer(dst_root, container_id);
+    }
+
+    if (suggested_container && window->parent() != suggested_container) {
+      aura::Window* focused = window->GetFocusManager()->GetFocusedWindow();
+      aura::client::ActivationClient* activation_client =
+          aura::client::GetActivationClient(window->GetRootWindow());
+      aura::Window* active = activation_client->GetActiveWindow();
+
+      aura::WindowTracker tracker;

[sky, 2012/07/20 15:06:07]

Why do you need to do this for focus/activation? If activation does change isn't
this going to lead to lots of unwanted events and side effects?

[oshima, 2012/07/20 17:03:11]

Moving window may reset the focus, and focused widget may
be deleted when moved (like bookmark bubble), so this is necessary.

+      if (focused)
+        tracker.Add(focused);
+      if (active && focused != active)
+        tracker.Add(active);
+
+      suggested_container->AddChild(window);
+
+      MoveAllTransientChildToNewRoot(dst_root, window);
+
+      // Restore focused/active window.
+      if (tracker.Contains(focused))
+        window->GetFocusManager()->SetFocusedWindow(focused, NULL);
+      else if (tracker.Contains(active))
+        activation_client->ActivateWindow(active);
+    }
+  }
+
   gfx::Point origin(bounds.origin());
   const gfx::Point display_origin =
       gfx::Screen::GetDisplayNearestWindow(window).bounds().origin();