Mac: Don't allow RenderWidgetHostViewCocoa to participate in autolayout.

content/browser/web_contents/web_contents_view_mac.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 <Carbon/Carbon.h>
 
 #import "content/browser/web_contents/web_contents_view_mac.h"
 
 #include <string>
 
@@ skipping 638 matching lines @@
 
 - (void)updateWebContentsVisibility {
   WebContentsImpl* webContents = [self webContents];
   if (!webContents || webContents->IsBeingDestroyed())
     return;
 
   const bool viewVisible = [self window] && ![self isHiddenOrHasHiddenAncestor];
   webContents->UpdateWebContentsVisibility(viewVisible);
 }
 
-// When the subviews require a layout, their size should be reset to the size
-// of this view. (It is possible for the size to get out of sync as an
-// optimization in preparation for an upcoming WebContentsView resize.
-// http://crbug.com/264207)
 - (void)resizeSubviewsWithOldSize:(NSSize)oldBoundsSize {
-  for (NSView* subview in self.subviews)
-    [subview setFrame:self.bounds];
+  // Subviews do not participate in auto layout unless the the size this view
+  // changes. This allows RenderWidgetHostViewMac::SetBounds(..) to select a
+  // size of the subview that differs from its superview in preparation for an
+  // upcoming WebContentsView resize.
+  // See http://crbug.com/264207 and http://crbug.com/655112.
+}
+
+- (void)setFrameSize:(NSSize)newSize {
+  [super setFrameSize:newSize];
+
+  // Perform manual layout of subviews, e.g., when the window size changes.
+  for (NSView* subview in [self subviews])
+    [subview setFrame:[self bounds]];
 }
 
 - (void)viewWillMoveToWindow:(NSWindow*)newWindow {
   NSWindow* oldWindow = [self window];
 
   NSNotificationCenter* notificationCenter =
       [NSNotificationCenter defaultCenter];
 
   // Occlusion is highly undesirable for browser tests, since it will
   // flakily change test behavior.
@@ skipping 35 matching lines @@
 
 - (void)viewDidHide {
   [self updateWebContentsVisibility];
 }
 
 - (void)viewDidUnhide {
   [self updateWebContentsVisibility];
 }
 
 @end