Mac: Fix SDK 10.11 Compile errors after clang roll in r387792

chrome/browser/ui/cocoa/tabs/tab_window_controller.mm

Index: chrome/browser/ui/cocoa/tabs/tab_window_controller.mm
diff --git a/chrome/browser/ui/cocoa/tabs/tab_window_controller.mm b/chrome/browser/ui/cocoa/tabs/tab_window_controller.mm
index 07baee691dd6d40137e006f61b944da0f3e13fb1..09025681aa91818b635eac2631a7ae0fe6cf1c56 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_window_controller.mm
+++ b/chrome/browser/ui/cocoa/tabs/tab_window_controller.mm
@@ -33,23 +33,15 @@
 @implementation TabWindowOverlayWindow
 
 - (const ui::ThemeProvider*)themeProvider {
-  if ([self parentWindow])
-    return [[[self parentWindow] windowController] themeProvider];
-  return NULL;
+  return [[self parentWindow] themeProvider];
 }
 
 - (ThemedWindowStyle)themedWindowStyle {
-  if ([self parentWindow])
-    return [[[self parentWindow] windowController] themedWindowStyle];
-  return NO;
+  return [[self parentWindow] themedWindowStyle];
 }
 
 - (NSPoint)themeImagePositionForAlignment:(ThemeImageAlignment)alignment {
-  if ([self parentWindow]) {
-    return [[[self parentWindow] windowController]
-        themeImagePositionForAlignment:alignment];
-  }
-  return NSZeroPoint;
+  return [[self parentWindow] themeImagePositionForAlignment:alignment];
 }
 
 @end