mac: Fix tab dragging visual bug in Yosemite.

chrome/browser/ui/cocoa/browser_window_controller_private.mm

Index: chrome/browser/ui/cocoa/browser_window_controller_private.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_controller_private.mm b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
index e1b7885bd2a795e90f310c1899a97478ede4af75..69f613f702041737bb56a20809130fdef0c4e5ac 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller_private.mm
+++ b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
@@ -567,8 +567,7 @@ willPositionSheet:(NSWindow*)sheet
   }
 
   // Ditto for the content view.
-  base::scoped_nsobject<NSView> contentView(
-      [[sourceWindow contentView] retain]);
+  base::scoped_nsobject<NSView> contentView([self.chromeContentView retain]);

[Scott Hess - ex-Googler, 2014/07/11 18:08:34]

Previously, |contentView| was essential because -removeFromSuperview would
remove the last reference.  Now chromeContentView_ should still contain a ref (I
think), so could the below just s/contentView/chromeContentView_/ ?

[erikchen, 2014/07/11 20:48:04]

I removed the local variable.

   // Disable autoresizing of subviews while we move views around. This prevents
   // spurious renderer resizes.
   [contentView setAutoresizesSubviews:NO];
@@ -585,7 +584,9 @@ willPositionSheet:(NSWindow*)sheet
   // no visual impact.  I have been unable to tickle it away with other window
   // or view manipulation Cocoa calls.  Stack added to suppressions_mac.txt.
   [contentView setAutoresizesSubviews:YES];
-  [destWindow setContentView:contentView];
+  [[destWindow contentView] addSubview:contentView
+                            positioned:NSWindowBelow
+                            relativeTo:nil];
 
   // Move the incognito badge if present.
   if ([self shouldShowAvatar]) {
@@ -852,7 +853,7 @@ willPositionSheet:(NSWindow*)sheet
     for (NSWindow* window in [[NSApplication sharedApplication] windows]) {
       if ([window
               isKindOfClass:NSClassFromString(@"NSToolbarFullScreenWindow")]) {
-        [window.contentView setHidden:YES];
+        [[window contentView] setHidden:YES];
       }
     }
   }
@@ -930,7 +931,7 @@ willPositionSheet:(NSWindow*)sheet
 }
 
 - (void)updateSubviewZOrder:(BOOL)inPresentationMode {
-  NSView* contentView = [[self window] contentView];
+  NSView* contentView = self.chromeContentView;
   NSView* toolbarView = [toolbarController_ view];
 
   if (inPresentationMode) {