Support detaching/attaching panels via inter-strip drags.

chrome/browser/ui/panels/detached_panel_browsertest.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 "chrome/browser/ui/panels/base_panel_browser_test.h"
 #include "chrome/browser/ui/panels/detached_panel_strip.h"
 #include "chrome/browser/ui/panels/native_panel.h"
 #include "chrome/browser/ui/panels/panel.h"
 #include "chrome/browser/ui/panels/panel_drag_controller.h"
 #include "chrome/browser/ui/panels/panel_manager.h"
@@ skipping 29 matching lines @@
   panel_manager->CloseAll();
 }
 
 IN_PROC_BROWSER_TEST_F(DetachedPanelBrowserTest, DragDetachedPanel) {
   PanelManager* panel_manager = PanelManager::GetInstance();
 
   // Create one detached panel.
   Panel* panel = CreatePanelWithBounds("Panel1", gfx::Rect(0, 0, 250, 200));
   panel_manager->MovePanelToStrip(panel, PanelStrip::DETACHED);
 
-  // Test that the detached panel can be dragged anywhere.
+  // Test that the detached panel can be dragged almost anywhere except getting
+  // close to the bottom of the docked area to trigger the attach.
   scoped_ptr<NativePanelTesting> panel_testing(
       NativePanelTesting::Create(panel->native_panel()));
   gfx::Point origin = panel->GetBounds().origin();
 
   panel_testing->PressLeftMouseButtonTitlebar(origin);
   EXPECT_EQ(origin, panel->GetBounds().origin());
 
   origin.Offset(-51, -102);
   panel_testing->DragTitlebar(origin);
   EXPECT_EQ(origin, panel->GetBounds().origin());
@@ skipping 162 matching lines @@
     CloseWindowAndWait(panel1->browser());
     EXPECT_FALSE(drag_controller->IsDragging());
 
     ASSERT_EQ(1, detached_strip->num_panels());
     EXPECT_TRUE(detached_strip->HasPanel(panel4));
     EXPECT_EQ(panel4_position, panel4->GetBounds().origin());
   }
 
   panel_manager->CloseAll();
 }