Do not allow window to drop below work area in aura during resize.

After this change:
- when a window is resized (by pulling at the bottom or lower corners), bottom resizing will stop at the top of the status area.
- a window can be dragged beyond the work area (well into status bar).
- left and right edge resizing is not affected by this change.
- top edge resizing is already not allowed to go beyond top work area and not affected by this change.

BUG=107807
TEST=tested on aura browser window drag and resizing.


Review URL: http://codereview.chromium.org/9085026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@116515 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 55 insertions, 2 deletions

diff --git a/ash/wm/toplevel_window_event_filter.cc b/ash/wm/toplevel_window_event_filter.cc
index c173ce7..1ff6edc 100644
--- a/ash/wm/toplevel_window_event_filter.cc
+++ b/ash/wm/toplevel_window_event_filter.cc
@@ -290,7 +290,17 @@ bool ToplevelWindowEventFilter::HandleDrag(aura::Window* target,
   gfx::Size size = GetSizeForDrag(bounds_change, target, &delta_x, &delta_y);
   gfx::Point origin = GetOriginForDrag(bounds_change, delta_x, delta_y);
 
-  target->SetBounds(gfx::Rect(origin, size));
+  gfx::Rect new_bounds(origin, size);
+  // Update bottom edge to stay in the work area when we are resizing
+  // by dragging the bottome edge or corners.
+  if (bounds_change & kBoundsChange_Resizes &&
+      origin.y() == target->bounds().y()) {
+    gfx::Rect work_area = gfx::Screen::GetMonitorWorkAreaNearestWindow(target);
+    if (new_bounds.bottom() > work_area.bottom())
+      new_bounds.Inset(0, 0, 0,
+                       new_bounds.bottom() - work_area.bottom());
+  }
+  target->SetBounds(new_bounds);
   return true;
 }
 
diff --git a/ash/wm/toplevel_window_event_filter_unittest.cc b/ash/wm/toplevel_window_event_filter_unittest.cc
index fb86a15..2ab742c 100644
--- a/ash/wm/toplevel_window_event_filter_unittest.cc
+++ b/ash/wm/toplevel_window_event_filter_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -320,5 +320,48 @@ TEST_F(ToplevelWindowEventFilterTest, DoubleClickCaptionTogglesMaximize) {
   EXPECT_FALSE(IsWindowMaximized(w1.get()));
 }
 
+TEST_F(ToplevelWindowEventFilterTest, BottomRightWorkArea) {
+  scoped_ptr<aura::Window> target(CreateWindow(HTBOTTOMRIGHT));
+  gfx::Rect work_area =
+      gfx::Screen::GetMonitorWorkAreaNearestWindow(target.get());
+  gfx::Point position = target->bounds().origin();
+  // Drag further than work_area bottom.
+  DragFromCenterBy(target.get(), 100, work_area.height());
+  // Position should not have changed.
+  EXPECT_EQ(position, target->bounds().origin());
+  // Size should have increased by 100, work_area.height() - target->bounds.y()
+  EXPECT_EQ(gfx::Size(200, work_area.height() - target->bounds().y()),
+            target->bounds().size());
+}
+
+TEST_F(ToplevelWindowEventFilterTest, BottomLeftWorkArea) {
+  scoped_ptr<aura::Window> target(CreateWindow(HTBOTTOMLEFT));
+  gfx::Rect work_area =
+      gfx::Screen::GetMonitorWorkAreaNearestWindow(target.get());
+  gfx::Point position = target->bounds().origin();
+  // Drag further than work_area bottom.
+  DragFromCenterBy(target.get(), -30, work_area.height());
+  // origin is now at 70, 100.
+  EXPECT_EQ(position.x() - 30, target->bounds().x());
+  EXPECT_EQ(position.y(), target->bounds().y());
+  // Size should have increased by 30, work_area.height() - target->bounds.y()
+  EXPECT_EQ(gfx::Size(130, work_area.height() - target->bounds().y()),
+            target->bounds().size());
+}
+
+TEST_F(ToplevelWindowEventFilterTest, BottomWorkArea) {
+  scoped_ptr<aura::Window> target(CreateWindow(HTBOTTOM));
+  gfx::Rect work_area =
+      gfx::Screen::GetMonitorWorkAreaNearestWindow(target.get());
+  gfx::Point position = target->bounds().origin();
+  // Drag further than work_area bottom.
+  DragFromCenterBy(target.get(), 0, work_area.height());
+  // Position should not have changed.
+  EXPECT_EQ(position, target->bounds().origin());
+  // Size should have increased by 0, work_area.height() - target->bounds.y()
+  EXPECT_EQ(gfx::Size(100, work_area.height() - target->bounds().y()),
+            target->bounds().size());
+}
+
 }  // namespace test
 }  // namespace aura