Mac: Fix rounded corners on browser windows on retina display.

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 484e0271f182ebfee893a70ec79efe6e26c93ecc..b43e1d0b0e55485fdc4ca0d94105202d6f7e37f6 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller_private.mm
+++ b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
@@ -523,6 +523,10 @@ willPositionSheet:(NSWindow*)sheet
   }
 }
 
+- (void)updateRoundedBottomCorners {
+  [[self tabContentArea] setRoundedBottomCorners:![self isFullscreen]];
+}
+
 - (void)adjustToolbarAndBookmarkBarForCompression:(CGFloat)compression {
   CGFloat newHeight =
       [toolbarController_ desiredHeightForCompression:compression];
@@ -912,6 +916,7 @@ willPositionSheet:(NSWindow*)sheet
   [self showFullscreenExitBubbleIfNecessary];
   browser_->WindowFullscreenStateChanged();
   [[[self window] cr_windowView] setWantsLayer:NO];
+  [self updateRoundedBottomCorners];
 }
 
 - (void)windowWillExitFullScreen:(NSNotification*)notification {
@@ -926,6 +931,7 @@ willPositionSheet:(NSWindow*)sheet
   if (notification)  // For System Fullscreen when non-nil.
     [self deregisterForContentViewResizeNotifications];
   browser_->WindowFullscreenStateChanged();
+  [self updateRoundedBottomCorners];
 }
 
 - (void)windowDidFailToEnterFullScreen:(NSWindow*)window {