ash: Refactor some code that snaps windows.

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/shell.h"
@@ skipping 68 matching lines @@
 bool CanMaximizeWindow(const aura::Window* window) {
   return window->GetProperty(aura::client::kCanMaximizeKey);
 }
 
 bool CanResizeWindow(const aura::Window* window) {
   return window->GetProperty(aura::client::kCanResizeKey);
 }
 
 bool CanSnapWindow(aura::Window* window) {
   // If a window has a maximum size defined, snapping may make it too big.
-  return window->delegate()->GetMaximumSize().IsEmpty();
+  return window->delegate() ? window->delegate()->GetMaximumSize().IsEmpty() :
+                              true;
 }
 
 bool IsWindowNormal(const aura::Window* window) {
   return IsWindowStateNormal(window->GetProperty(aura::client::kShowStateKey));
 }
 
 bool IsWindowStateNormal(ui::WindowShowState state) {
   return state == ui::SHOW_STATE_NORMAL || state == ui::SHOW_STATE_DEFAULT;
 }
 
@@ skipping 32 matching lines @@
 }
 
 void CenterWindow(aura::Window* window) {
   const gfx::Display display =
       Shell::GetScreen()->GetDisplayNearestWindow(window);
   gfx::Rect center = display.work_area();
   center.ClampToCenteredSize(window->bounds().size());
   window->SetBounds(center);
 }
 
+void SnapWindow(aura::Window* window, internal::SnapSizer::Edge edge) {
+  if (!CanSnapWindow(window))
+    return;
+  internal::SnapSizer sizer(window, gfx::Point(), edge,
+      internal::SnapSizer::OTHER_INPUT);
+  if (wm::IsWindowFullscreen(window) || wm::IsWindowMaximized(window)) {
+    // Before we can set the bounds we need to restore the window.
+    // Restoring the window will set the window to its restored bounds.
+    // To avoid an unnecessary bounds changes (which may have side effects)
+    // we set the restore bounds to the bounds we want, restore the window,
+    // then reset the restore bounds. This way no unnecessary bounds
+    // changes occurs and the original restore bounds is remembered.
+    gfx::Rect restore = *GetRestoreBoundsInScreen(window);
+    SetRestoreBoundsInParent(window, sizer.GetSnapBounds(window->bounds()));
+    wm::RestoreWindow(window);
+    SetRestoreBoundsInScreen(window, restore);
+  } else {
+    window->SetBounds(sizer.GetSnapBounds(window->bounds()));
+  }
+}
+
 ui::Layer* RecreateWindowLayers(aura::Window* window, bool set_bounds) {
   const gfx::Rect bounds = window->bounds();
   ui::Layer* old_layer = window->RecreateLayer();
   DCHECK(old_layer);
   for (aura::Window::Windows::const_iterator it = window->children().begin();
        it != window->children().end();
        ++it) {
     // Maintain the hierarchy of the detached layers.
     old_layer->Add(RecreateWindowLayers(*it, set_bounds));
   }
@@ skipping 58 matching lines @@
       x_offset = work_area.right() - bounds->x() - kMinimumOnScreenArea;
     } else if (bounds->right() < work_area.x()) {
       x_offset = work_area.x() - bounds->right() + kMinimumOnScreenArea;
     }
     bounds->Offset(x_offset, y_offset);
   }
 }
 
 }  // namespace wm
 }  // namespace ash