Mac: Comment tweaks requested in http://codereview.chromium.org/3549004

chrome/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2010 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.
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "chrome/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include "chrome/browser/chrome_thread.h"
 #include "app/surface/io_surface_support_mac.h"
@@ skipping 272 matching lines @@
   // method does not pass the message up the responder chain, it handles it
   // directly."
   // That's bad, we want the next responder (RWHVMac) to handle this event to
   // dispatch it to the renderer.
   [[self nextResponder] rightMouseDown:event];
 }
 
 - (void)globalFrameDidChange:(NSNotification*)notification {
   globalFrameDidChangeCGLLockCount_++;
   CGLLockContext(cglContext_);
+  // This call to -update can call -globalFrameDidChange: again, see
+  // http://crbug.com/55754 comments 22 and 24.
   [glContext_ update];
 
   // You would think that -update updates the viewport. You would be wrong.
   CGLSetCurrentContext(cglContext_);
   NSSize size = [self frame].size;
   glViewport(0, 0, size.width, size.height);
 
   CGLUnlockContext(cglContext_);
   globalFrameDidChangeCGLLockCount_--;
 
@@ skipping 36 matching lines @@
 - (void)viewWillMoveToWindow:(NSWindow*)newWindow {
   // Stop the display link thread while the view is not visible.
   if (newWindow) {
     if (displayLink_ && !CVDisplayLinkIsRunning(displayLink_))
       CVDisplayLinkStart(displayLink_);
   } else {
     if (displayLink_ && CVDisplayLinkIsRunning(displayLink_))
       CVDisplayLinkStop(displayLink_);
   }
 
-  // If hole pushing is enabled, inform the window hosing this accelerated view
-  // that it needs to be opaque.
+  // If hole punching is enabled, inform the window hosting this accelerated
+  // view that it needs to be opaque.
   if (!CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableHolePunching)) {
     if ([[self window] respondsToSelector:@selector(underlaySurfaceRemoved)]) {
       [static_cast<id>([self window]) underlaySurfaceRemoved];
     }
 
     if ([newWindow respondsToSelector:@selector(underlaySurfaceAdded)]) {
       [static_cast<id>(newWindow) underlaySurfaceAdded];
     }
   }
@@ skipping 2086 matching lines @@
   if (!string) return NO;
 
   // If the user is currently using an IME, confirm the IME input,
   // and then insert the text from the service, the same as TextEdit and Safari.
   [self confirmComposition];
   [self insertText:string];
   return YES;
 }
 
 @end