[Mac] Opt browser window controller out of being a touch bar provider

chrome/browser/ui/cocoa/browser_window_controller.mm

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 
 #include <cmath>
 #include <numeric>
 #include <utility>
 
@@ skipping 412 matching lines @@
   [tabStripController_ browserWillBeDestroyed];
   [findBarCocoaController_ browserWillBeDestroyed];
   [downloadShelfController_ browserWillBeDestroyed];
   [bookmarkBarController_ browserWillBeDestroyed];
   [avatarButtonController_ browserWillBeDestroyed];
   [bookmarkBubbleController_ browserWillBeDestroyed];
 
   [super dealloc];
 }
 
+// Hack to address crbug.com/667274
+// On TouchBar MacBooks, the touch bar machinery retains a reference
+// to the browser window controller (which is an NSTouchBarProvider by
+// default) but doesn't release it if Chrome quits before it takes the
+// key window (for example, quitting from the Dock icon context menu.)
+//
+// If the window denies being a touch bar provider, it's never added
+// to the set of providers and the reference is never taken. This
+// prevents us from providing a touch bar from the window directly
+// but descendant responders can still provide one.
+//
+// rdar://29467717
+- (BOOL)conformsToProtocol:(Protocol*)protocol {
+  if ([protocol isEqual:NSProtocolFromString(@"NSFunctionBarProvider")] ||
+      [protocol isEqual:NSProtocolFromString(@"NSTouchBarProvider")]) {
+    return NO;
+  }
+  return [super conformsToProtocol:protocol];
+}
+
 - (gfx::Rect)enforceMinWindowSize:(gfx::Rect)bounds {
   gfx::Rect checkedBounds = bounds;
 
   NSSize minSize = [[self window] minSize];
   if (bounds.width() < minSize.width)
       checkedBounds.set_width(minSize.width);
   if (bounds.height() < minSize.height)
       checkedBounds.set_height(minSize.height);
 
   return checkedBounds;
@@ skipping 1531 matching lines @@
 
 - (NSRect)savedRegularWindowFrame {
   return savedRegularWindowFrame_;
 }
 
 - (BOOL)isFullscreenTransitionInProgress {
   return enteringAppKitFullscreen_ || exitingAppKitFullscreen_;
 }
 
 @end  // @implementation BrowserWindowController(WindowType)