[Mac] Avoid "adding unknown subview" warning.

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 e8465ef4a9b2b78128128a98cc057b19917586c3..a7feb96f83baed912919e358b4841e2055eab527 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_window_controller.mm
+++ b/chrome/browser/ui/cocoa/tabs/tab_window_controller.mm
@@ -395,9 +395,13 @@
   [visualEffectView setBlendingMode:NSVisualEffectBlendingModeBehindWindow];
   [visualEffectView setState:NSVisualEffectStateFollowsWindowActiveState];
 
-  [rootView addSubview:visualEffectView
-            positioned:NSWindowBelow
-            relativeTo:nil];
+  if (base::mac::IsAtLeastOS10_10()) {

[erikchen, 2016/09/20 23:07:47]

This CL contains references to both IsAtMost 10.10 and IsAtLeast10.10, for which
10.10 overlaps. It's not clear to me whether you're trying to change 10.11+ or
10.10+

[shrike, 2016/09/20 23:27:17]

I'm finding this isAtLeast/IsAtMost confusing. I believe I have used the correct
logic in this and the other location you mention, but I have changed the logic
here so that it's also IsAtMost10.10().

+    [[window contentView] addSubview:visualEffectView];
+  } else {
+    [rootView addSubview:visualEffectView
+              positioned:NSWindowBelow
+              relativeTo:nil];
+  }
 
   // Make the |tabStripBackgroundView_| a child of the NSVisualEffectView.
   [tabStripBackgroundView_ setFrame:[visualEffectView bounds]];