Always set NSTexturedBackgroundWindowMask on app windows.

chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm

Index: chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm b/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm
index ecb10c0b1b6af5a339dfe71b3c331b4a6363862f..3843f47a71797bbe040f71938f239f6ff7e4a501 100644
--- a/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm
+++ b/chrome/browser/ui/cocoa/apps/native_app_window_cocoa.mm
@@ -223,9 +223,7 @@ std::vector<gfx::Rect> CalculateNonDraggableRegions(
 @end
 
 @interface ShellCustomFrameNSWindow : ShellNSWindow
-
 - (void)drawCustomFrameRect:(NSRect)rect forView:(NSView*)view;
-
 @end
 
 @implementation ShellCustomFrameNSWindow
@@ -248,12 +246,14 @@ std::vector<gfx::Rect> CalculateNonDraggableRegions(
 
 @end
 
-@interface ShellFramelessNSWindow : ShellCustomFrameNSWindow
-
+@interface ShellFramelessNSWindow : ShellNSWindow
+- (void)drawCustomFrameRect:(NSRect)rect forView:(NSView*)view;

[tapted, 2014/05/29 03:35:28]

I'd move this up into the ShellNSWindow interface (and move empty implementation
into ShellNSWindow implementation). Then ShellCustomFrameNSWindow overrides it.
Feels more natural than just happening to have the same method implemented on
both child classes :)

[jackhou1, 2014/05/29 04:09:40]

ShellNSWindow is used to draw native frames, so it needs to call the default
implementation.

 @end
 
 @implementation ShellFramelessNSWindow
 
+- (void)drawCustomFrameRect:(NSRect)rect forView:(NSView*)view {}
+
 + (NSRect)frameRectForContentRect:(NSRect)contentRect
                         styleMask:(NSUInteger)mask {
   return contentRect;
@@ -373,14 +373,10 @@ NativeAppWindowCocoa::NativeAppWindowCocoa(
 
 NSUInteger NativeAppWindowCocoa::GetWindowStyleMask() const {
   NSUInteger style_mask = NSTitledWindowMask | NSClosableWindowMask |
-                          NSMiniaturizableWindowMask;
+                          NSMiniaturizableWindowMask |
+                          NSTexturedBackgroundWindowMask;

[tapted, 2014/05/29 03:35:28]

The documentation suggests that adding this has a side-effect of "always"
drawing the window with rounded corners.. but I guess that's fine since I don't
think there's a way for a packaged app to have square corners currently if they
wanted to..

[jackhou1, 2014/05/29 04:09:40]

Yeah, and I think this only applies for native frames. I.e. we can still make
ShellCustomFrameNSWindow draw whatever we want. That said,
ShellFramelessNSWindow seems to have rounded bottom corners regardless of
whether this is set.

   if (shows_resize_controls_)
     style_mask |= NSResizableWindowMask;
-  if (!has_frame_ ||
-      !CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kAppsUseNativeFrame)) {
-    style_mask |= NSTexturedBackgroundWindowMask;
-  }
   return style_mask;
 }