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

chrome/browser/ui/cocoa/tabs/tab_view.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.
 
 #import "chrome/browser/ui/cocoa/tabs/tab_view.h"
 
 #include "base/logging.h"
 #import "base/mac/mac_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "chrome/browser/themes/theme_service.h"
 #import "chrome/browser/ui/cocoa/nsview_additions.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_controller.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_window_controller.h"
 #import "chrome/browser/ui/cocoa/themed_window.h"
 #import "chrome/browser/ui/cocoa/view_id_util.h"
 #include "grit/generated_resources.h"
 #include "grit/theme_resources.h"
 #include "grit/theme_resources_standard.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
 
 namespace {
 
 // Constants for inset and control points for tab shape.
 const CGFloat kInsetMultiplier = 2.0/3.0;
 const CGFloat kControlPoint1Multiplier = 1.0/3.0;
 const CGFloat kControlPoint2Multiplier = 3.0/8.0;
 
 // The amount of time in seconds during which each type of glow increases, holds
 // steady, and decreases, respectively.
@@ skipping 615 matching lines @@
     // close.
     if ([self hitTest:upLocation])
       [controller_ closeTab:self];
   }
 }
 
 - (void)drawRect:(NSRect)dirtyRect {
   const CGFloat lineWidth = [self cr_lineWidth];
 
   NSGraphicsContext* context = [NSGraphicsContext currentContext];
-  [context saveGraphicsState];
+  gfx::ScopedNSGraphicsContextSaveGState scopedGState(context);
 
   ThemeService* themeProvider =
       static_cast<ThemeService*>([[self window] themeProvider]);
   [context setPatternPhase:[[self window] themePatternPhase]];
 
   NSRect rect = [self bounds];
   NSBezierPath* path = [self bezierPathForRect:rect];
 
   BOOL selected = [self state];
   // Don't draw the window/tab bar background when selected, since the tab
@@ skipping 28 matching lines @@
 
   [context saveGraphicsState];
   [path addClip];
 
   // Use the same overlay for the selected state and for hover and alert glows;
   // for the selected state, it's fully opaque.
   CGFloat hoverAlpha = [self hoverAlpha];
   CGFloat alertAlpha = [self alertAlpha];
   if (selected || hoverAlpha > 0 || alertAlpha > 0) {
     // Draw the selected background / glow overlay.
-    [context saveGraphicsState];
+    gfx::ScopedNSGraphicsContextSaveGState drawHoverState(context);
     CGContextRef cgContext = static_cast<CGContextRef>([context graphicsPort]);
     CGContextBeginTransparencyLayer(cgContext, 0);
     if (!selected) {
       // The alert glow overlay is like the selected state but at most at most
       // 80% opaque. The hover glow brings up the overlay's opacity at most 50%.
       CGFloat backgroundAlpha = 0.8 * alertAlpha;
       backgroundAlpha += (1 - backgroundAlpha) * 0.5 * hoverAlpha;
       CGContextSetAlpha(cgContext, backgroundAlpha);
     }
     [path addClip];
-    [context saveGraphicsState];
-    [super drawBackground];
-    [context restoreGraphicsState];
+    {
+      gfx::ScopedNSGraphicsContextSaveGState drawBackgroundState(context);
+      [super drawBackground];
+    }
 
     // Draw a mouse hover gradient for the default themes.
     if (!selected && hoverAlpha > 0) {
       if (themeProvider && !hasBackgroundImage) {
         scoped_nsobject<NSGradient> glow([NSGradient alloc]);
         [glow initWithStartingColor:[NSColor colorWithCalibratedWhite:1.0
                                         alpha:1.0 * hoverAlpha]
                         endingColor:[NSColor colorWithCalibratedWhite:1.0
                                                                 alpha:0.0]];
 
         NSPoint point = hoverPoint_;
         point.y = NSHeight(rect);
         [glow drawFromCenter:point
                       radius:0.0
                     toCenter:point
                       radius:NSWidth(rect) / 3.0
                      options:NSGradientDrawsBeforeStartingLocation];
 
         [glow drawInBezierPath:path relativeCenterPosition:hoverPoint_];
       }
     }
 
     CGContextEndTransparencyLayer(cgContext);
-    [context restoreGraphicsState];
   }
 
   BOOL active = [[self window] isKeyWindow] || [[self window] isMainWindow];
   CGFloat borderAlpha = selected ? (active ? 0.3 : 0.2) : 0.2;
   NSColor* borderColor = [NSColor colorWithDeviceWhite:0.0 alpha:borderAlpha];
   NSColor* highlightColor = themeProvider ? themeProvider->GetNSColor(
       themeProvider->UsingDefaultTheme() ?
           ThemeService::COLOR_TOOLBAR_BEZEL :
           ThemeService::COLOR_TOOLBAR, true) : nil;
 
   // Draw the top inner highlight within the currently selected tab if using
   // the default theme.
   if (selected && themeProvider && themeProvider->UsingDefaultTheme()) {
     NSAffineTransform* highlightTransform = [NSAffineTransform transform];
     [highlightTransform translateXBy:lineWidth yBy:-lineWidth];
     scoped_nsobject<NSBezierPath> highlightPath([path copy]);
     [highlightPath transformUsingAffineTransform:highlightTransform];
     [highlightColor setStroke];
     [highlightPath setLineWidth:lineWidth];
     [highlightPath stroke];
     highlightTransform = [NSAffineTransform transform];
     [highlightTransform translateXBy:-2 * lineWidth yBy:0.0];
     [highlightPath transformUsingAffineTransform:highlightTransform];
     [highlightPath stroke];
   }
 
   [context restoreGraphicsState];
 
   // Draw the top stroke.
-  [context saveGraphicsState];
-  [borderColor set];
-  [path setLineWidth:lineWidth];
-  [path stroke];
-  [context restoreGraphicsState];
+  {
+    gfx::ScopedNSGraphicsContextSaveGState drawBorderState(context);
+    [borderColor set];
+    [path setLineWidth:lineWidth];
+    [path stroke];
+  }
 
   // Mimic the tab strip's bottom border, which consists of a dark border
   // and light highlight.
   if (![controller_ active]) {
     [path addClip];
     NSRect borderRect = rect;
     borderRect.origin.y = lineWidth;
     borderRect.size.height = lineWidth;
     [borderColor set];
     NSRectFillUsingOperation(borderRect, NSCompositeSourceOver);
 
     borderRect.origin.y = 0;
     [highlightColor set];
     NSRectFillUsingOperation(borderRect, NSCompositeSourceOver);
   }
-
-  [context restoreGraphicsState];
 }
 
 - (void)viewDidMoveToWindow {
   [super viewDidMoveToWindow];
   if ([self window]) {
     [controller_ updateTitleColor];
   }
 }
 
 - (void)setClosing:(BOOL)closing {
@@ skipping 258 matching lines @@
                                  topRight.y)
        controlPoint2:NSMakePoint(bottomRight.x - baseControlPointOutset,
                                  bottomRight.y)];
   [path lineToPoint:NSMakePoint(bottomRight.x + lineWidth, bottomRight.y)];
   [path lineToPoint:NSMakePoint(bottomRight.x + lineWidth,
                                 bottomRight.y - (2 * lineWidth))];
   return path;
 }
 
 @end  // @implementation TabView(Private)