Add frameless for ShellWindow on gtk.

chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm

Index: chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm b/chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm
index 3958dce10d4782421e74191fd37c0cb0f408b612..88eb65c85c3d9e0cc07a1381cb1a278ee34118e4 100644
--- a/chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm
+++ b/chrome/browser/ui/cocoa/extensions/shell_window_cocoa.mm
@@ -93,9 +93,13 @@ ShellWindowCocoa::ShellWindowCocoa(Profile* profile,
   NSRect cocoa_bounds = NSMakeRect(params.bounds.x(),
       NSHeight(main_screen_rect) - params.bounds.y() - params.bounds.height(),
       params.bounds.width(), params.bounds.height());
-  NSUInteger style_mask = NSTitledWindowMask | NSClosableWindowMask |
-                          NSMiniaturizableWindowMask | NSResizableWindowMask |
-                          NSTexturedBackgroundWindowMask;
+  NSUInteger style_mask = NSTexturedBackgroundWindowMask;
+  // Hide titlebar when {frame: 'none'} on ShellWindow.

[jeremy, 2012/08/05 08:04:21]

nit: on -> specified on

+  if (params.frame == ShellWindow::CreateParams::FRAME_NONE)
+    style_mask |= NSBorderlessWindowMask;
+  else
+    style_mask |= NSTitledWindowMask | NSClosableWindowMask |
+                  NSMiniaturizableWindowMask | NSResizableWindowMask;
   scoped_nsobject<NSWindow> window([[ShellNSWindow alloc]
       initWithContentRect:cocoa_bounds
                 styleMask:style_mask