Mac: Fix regression in NTP detached bookmark bar colours.

chrome/browser/cocoa/bookmark_bar_toolbar_view.mm

 // Copyright (c) 2009 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/cocoa/bookmark_bar_toolbar_view.h"
 
 #include "app/gfx/canvas_paint.h"
 #include "app/theme_provider.h"
 #include "base/gfx/rect.h"
 #include "chrome/browser/browser_theme_provider.h"
@@ skipping 80 matching lines @@
   NSColor* toolbarColor =
       [[self gtm_theme] backgroundColorForStyle:GTMThemeStyleToolBar
                                           state:GTMThemeStateActiveWindow];
   // workaround for default theme
   // TODO(alcor) next GTM update return nil for background color if not set;
   // http://crbug.com/25196
   if ([toolbarColor isEqual:[NSColor colorWithCalibratedWhite:0.5 alpha:1.0]])
     toolbarColor = nil;
   if (!toolbarColor)
     toolbarColor = [NSColor colorWithCalibratedWhite:0.9 alpha:1.0];
-  [[toolbarColor colorWithAlphaComponent:morph] set];  // Set with opacity.
+  CGFloat alpha = morph * [toolbarColor alphaComponent];
+  [[toolbarColor colorWithAlphaComponent:alpha] set];  // Set with opacity.
   [border fill];
 
   // Fade in/out the background.
   [context saveGraphicsState];
   [border setClip];
   CGContextRef cgContext = (CGContextRef)[context graphicsPort];
   CGContextBeginTransparencyLayer(cgContext, NULL);
   CGContextSetAlpha(cgContext, 1 - morph);
   [context setPatternPhase:[self gtm_themePatternPhase]];
   [self drawBackground];
   CGContextEndTransparencyLayer(cgContext);
   [context restoreGraphicsState];
 
   // Draw the border of the rounded rectangle.
   NSColor* borderColor =
       [[self gtm_theme] strokeColorForStyle:GTMThemeStyleToolBarButton
                                       state:GTMThemeStateActiveWindow];
-  [[borderColor colorWithAlphaComponent:morph] set];  // Set with opacity.
+  alpha = morph * [borderColor alphaComponent];
+  [[borderColor colorWithAlphaComponent:alpha] set];  // Set with opacity.
   [border stroke];
 
   // Fade in/out the divider.
   // TODO(viettrungluu): It's not obvious that this divider lines up exactly
   // with |BackgroundGradientView|'s (in fact, it probably doesn't).
-  [[[self strokeColor] colorWithAlphaComponent:(1 - morph)] set];
+  NSColor* strokeColor = [self strokeColor];
+  alpha = (1 - morph) * [strokeColor alphaComponent];
+  [[strokeColor colorWithAlphaComponent:alpha] set];
   NSBezierPath* divider = [NSBezierPath bezierPath];
   NSPoint dividerStart =
       NSMakePoint(morph * bookmarks::kNTPBookmarkBarPadding + morph * 0.5,
                   morph * bookmarks::kNTPBookmarkBarPadding + morph * 0.5);
   CGFloat dividerWidth =
       NSWidth(bounds) - 2 * morph * bookmarks::kNTPBookmarkBarPadding - 2 * 0.5;
   [divider moveToPoint:dividerStart];
   [divider relativeLineToPoint:NSMakePoint(dividerWidth, 0)];
   [divider stroke];
 
   // Restore the graphics context.
   [context restoreGraphicsState];
 }
 
 @end  // @implementation BookmarkBarToolbarView