[Mac] Avoid "adding unknown subview" warning.

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

 // Copyright (c) 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/tabs/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 211 matching lines @@
 // http://www.cocoabuilder.com/archive/cocoa/219261-conditional-mousedowncanmovewindow-for-nsview.html
 // http://www.cocoabuilder.com/archive/cocoa/92973-brushed-metal-window-dragging.html
 - (void)trackClickForWindowMove:(NSEvent*)event;
 @end
 
 @implementation TabStripControllerDragBlockingView
 - (BOOL)mouseDownCanMoveWindow {
   return NO;
 }
 
+// Called by AppKit to check if dragging this view should move the window.
+// NSButton overrides this method in the same way so dragging window buttons
+// has no effect.
+- (NSRect)_opaqueRectForWindowMoveWhenInTitlebar {

[tapted, 2016/10/10 23:38:06]

nit: we typically forward-declare these - I guess it's only strictly necessary
when calling [super ..] but it helps document where the private methods are
coming from. E.g. in a `@interface NSView (PrivateAPI)` at the top of the file.
(and we haven't started putting private APIs into sdk_forward_declarations, so I
guess we should copy it in tab_view.mm as well, [or give it its own header..]).

[Eugene But (OOO till 7-30), 2016/10/11 00:33:10]

Done.

+ return [self bounds];

[tapted, 2016/10/10 23:38:06]

Maybe comment here what the base class returns? (I'm guessing NSZeroRect?) --
i.e. say why [self bounds] is the right thing to convince AppKit not to move the
window

[Eugene But (OOO till 7-30), 2016/10/11 00:33:10]

Done in predeclaration.

+}
+
 - (id)initWithFrame:(NSRect)frameRect
          controller:(TabStripController*)controller {
   if ((self = [super initWithFrame:frameRect])) {
     controller_ = controller;
   }
   return self;
 }
 
 // In "rapid tab closure" mode (i.e., the user is clicking close tab buttons in
 // rapid succession), the animations confuse Cocoa's hit testing (which appears
@@ skipping 2081 matching lines @@
   for (int i = 0; i < tabStripModel_->count(); i++) {
     [self updateIconsForContents:tabStripModel_->GetWebContentsAt(i) atIndex:i];
   }
 }
 
 - (void)setVisualEffectsDisabledForFullscreen:(BOOL)fullscreen {
   [tabStripView_ setVisualEffectsDisabledForFullscreen:fullscreen];
 }
 
 @end