Support detaching/attaching panels via inter-strip drags.

chrome/browser/ui/panels/detached_panel_browsertest.cc

Index: chrome/browser/ui/panels/detached_panel_browsertest.cc
diff --git a/chrome/browser/ui/panels/detached_panel_browsertest.cc b/chrome/browser/ui/panels/detached_panel_browsertest.cc
index 885cc1dce8c2e53c508ad8bb617b9825b76ba102..7db58e1a497782bf95afc8d88b71c9eb7ebcbb99 100644
--- a/chrome/browser/ui/panels/detached_panel_browsertest.cc
+++ b/chrome/browser/ui/panels/detached_panel_browsertest.cc
@@ -47,7 +47,8 @@ IN_PROC_BROWSER_TEST_F(DetachedPanelBrowserTest, DragDetachedPanel) {
   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();