Don't use drag to corner resizing for unresizable windows

ash/wm/workspace/workspace_window_resizer.cc

Index: ash/wm/workspace/workspace_window_resizer.cc
diff --git a/ash/wm/workspace/workspace_window_resizer.cc b/ash/wm/workspace/workspace_window_resizer.cc
index ab5782a347c6afe9c06cd8cae5286db063e5e9a5..52757bc2f152803639f5e29c7cc9383bcaa79589 100644
--- a/ash/wm/workspace/workspace_window_resizer.cc
+++ b/ash/wm/workspace/workspace_window_resizer.cc
@@ -29,6 +29,8 @@
 #include "ui/compositor/layer.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/transform.h"
+#include "ui/views/widget/widget.h"
+#include "ui/views/widget/widget_delegate.h"
 
 namespace ash {
 
@@ -286,8 +288,14 @@ void WorkspaceWindowResizer::Drag(const gfx::Point& location_in_parent,
   wm::ConvertPointToScreen(window()->parent(), &location_in_screen);
   const bool in_original_root =
       wm::GetRootWindowAt(location_in_screen) == window()->GetRootWindow();
+
+  bool resizeable = true;
+  views::Widget* widget = views::Widget::GetWidgetForNativeWindow(window());

[sky, 2012/11/12 03:56:08]

If all windows were created by widgets, this change would be reasonable. But
that need not be the case. The property approach is better since it can work
with a window created in any way.

[Mr4D (OOO till 08-26), 2012/11/12 18:25:01]

Done.

+  if (widget && widget->widget_delegate())
+    resizeable = widget->widget_delegate()->CanResize();
+
   // Hide a phantom window for snapping if the cursor is in another root window.
-  if (in_original_root) {
+  if (in_original_root && resizeable) {
     UpdateSnapPhantomWindow(location_in_parent, bounds);
   } else {
     snap_type_ = SNAP_NONE;