Add ash-enable-sticky-edges for 'sticky' instead of 'snap' behavior.

ash/wm/window_util.cc

 // Copyright (c) 2012 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 "ash/wm/window_util.h"
 
 #include <vector>
 
 #include "ash/ash_constants.h"
+#include "ash/ash_switches.h"
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/activation_controller.h"
 #include "ash/wm/window_properties.h"
+#include "ash/wm/workspace/workspace_window_resizer.h"
+#include "base/command_line.h"
 #include "ui/aura/client/activation_client.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/compositor/layer.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/corewm/window_util.h"
 #include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 
+namespace {
+
+// Number of pixels of mouse movement required before windows drag or resize
+// beyond the edge of a workspace.
+const int kWindowStickySize = 64;
+
+}
+
 namespace ash {
 namespace wm {
 
 // TODO(beng): replace many of these functions with the corewm versions.
 void ActivateWindow(aura::Window* window) {
   views::corewm::ActivateWindow(window);
 }
 
 void DeactivateWindow(aura::Window* window) {
   views::corewm::DeactivateWindow(window);
@@ skipping 173 matching lines @@
       target->GetWidget()->GetNativeView()->GetRootWindow();
   if (!target_root || target_root == window->GetRootWindow())
     return false;
   aura::Window* window_container =
       ash::Shell::GetContainer(target_root, window->parent()->id());
   // Move the window to the target launcher.
   window_container->AddChild(window);
   return true;
 }
 
+bool ShouldStickToEdge(int distance_from_edge) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kAshEnableStickyEdges)) {
+    return distance_from_edge < 0 &&
+           distance_from_edge > -kWindowStickySize;
+  } else {
+    const int sticky_size = internal::WorkspaceWindowResizer::kScreenEdgeInset;

[flackr, 2013/04/16 00:32:14]

Assuming this method stays here we should probably move this constant to this
file and rename it more appropriately, i.e. kWindowSnapSize (The inset behavior
is only a consequence of restoring windows with snap behavior turned on). Then
there would be no need to assign to a local const int.

[stevenjb, 2013/04/16 20:08:20]

Moved back.

+    return distance_from_edge < sticky_size &&
+           distance_from_edge > -sticky_size * 2;
+  }
+}
+
 }  // namespace wm
 }  // namespace ash