Add and use gfx::ScopedNSGraphicsContextState (ui/gfx/scoped_ns_graphics_context_state_mac.h).

chrome/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2011 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 "base/command_line.h"
 #include "base/logging.h"
@@ skipping 24 matching lines @@
 #include "content/common/gpu/gpu_messages.h"
 #include "content/common/native_web_keyboard_event.h"
 #include "content/common/plugin_messages.h"
 #include "content/common/view_messages.h"
 #include "skia/ext/platform_canvas.h"
 #import "third_party/mozilla/ComplexTextInputPanel.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/mac/WebInputEventFactory.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
 #include "ui/gfx/gl/gl_switches.h"
+#include "ui/gfx/scoped_ns_graphics_context_state_mac.h"
 #include "ui/gfx/surface/io_surface_support_mac.h"
 #include "webkit/glue/webaccessibility.h"
 #include "webkit/plugins/npapi/webplugin.h"
 
 using WebKit::WebInputEvent;
 using WebKit::WebInputEventFactory;
 using WebKit::WebMouseEvent;
 using WebKit::WebMouseWheelEvent;
 
 static inline int ToWebKitModifiers(NSUInteger flags) {
@@ skipping 354 matching lines @@
   CGLUnlockContext(cglContext_);
 }
 
 - (void)drawRect:(NSRect)rect {
   if (!CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableHolePunching)) {
     const NSRect* dirtyRects;
     int dirtyRectCount;
     [self getRectsBeingDrawn:&dirtyRects count:&dirtyRectCount];
 
-    [NSGraphicsContext saveGraphicsState];
+    gfx::ScopedNSGraphicsContextState scopedGState;

[Nico, 2011/04/26 17:56:28]

hm, this line in itself isn't very obvious. Maybe

    gfx::ScopedSaveNSGraphicsContextState scopedGState;

(i.e. add "Save" to type name)

[Robert Sesek, 2011/04/26 18:50:53]

This matches the CGContext version...

 
     // Mask out any cutout rects--somewhat counterintuitively cutout rects are
     // places where clearColor is *not* drawn. The trick is that drawing nothing
     // lets the parent view (i.e., the web page) show through, whereas drawing
     // clearColor punches a hole in the window (letting OpenGL show through).
     if ([cutoutRects_.get() count] > 0) {
       NSBezierPath* path = [NSBezierPath bezierPath];
       // Trace the bounds clockwise to give a base clip rect of the whole view.
       NSRect bounds = [self bounds];
       [path moveToPoint:bounds.origin];
       [path lineToPoint:NSMakePoint(NSMinX(bounds), NSMaxY(bounds))];
       [path lineToPoint:NSMakePoint(NSMaxX(bounds), NSMaxY(bounds))];
       [path lineToPoint:NSMakePoint(NSMaxX(bounds), NSMinY(bounds))];
       [path closePath];
 
       // Then trace each cutout rect counterclockwise to remove that region from
       // the clip region.
       for (NSValue* rectWrapper in cutoutRects_.get()) {
         [path appendBezierPathWithRect:[rectWrapper rectValue]];
       }
 
       [path addClip];
     }
 
     // Punch a hole so that the OpenGL view shows through.
     [[NSColor clearColor] set];
     NSRectFillList(dirtyRects, dirtyRectCount);
-
-    [NSGraphicsContext restoreGraphicsState];
   }
 
   [self drawView];
 }
 
 - (void)rightMouseDown:(NSEvent*)event {
   // The NSResponder documentation: "Note: The NSView implementation of this
   // 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
@@ skipping 2443 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