mac: Attempt to fix startup regression after r174653 more

chrome/browser/ui/cocoa/tabs/tab_strip_controller.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 "chrome/browser/ui/cocoa/tabs/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 154 matching lines @@
   for (ui::ScaleFactor scale_factor : ui::GetSupportedScaleFactors()) {
     float scale = GetScaleFactorScale(scale_factor);
     NSBitmapImageRep *bmpImageRep = [[NSBitmapImageRep alloc]
         initWithBitmapDataPlanes:NULL
                       pixelsWide:size.width * scale
                       pixelsHigh:size.height * scale
                    bitsPerSample:8
                  samplesPerPixel:4
                         hasAlpha:YES
                         isPlanar:NO
-                  colorSpaceName:NSCalibratedRGBColorSpace
-                    bitmapFormat:NSAlphaFirstBitmapFormat

[sail, 2013/01/04 22:03:35]

Does this help because it prevents a format conversion? Seems like a good idea
to leave this out anyways.

[Nico, 2013/01/04 22:05:55]

I think this is the default, I omitted this part for brevity.

+                  colorSpaceName:NSDeviceRGBColorSpace

[sail, 2013/01/04 22:03:35]

Does this help because it now matches the destination color space or because it
matches the source image color space?

If it's the second then can we grab the color space from the source images and
use it here.

If it's the first then should we document that?

[Nico, 2013/01/04 22:05:55]

I don't know if it helps. Resource images are loaded with the
kCGGenericColorspace (or how that's called); not sure if that's intentional. So
previously this wouldn't cause a conversion, but it would at paint time. Now it
converts earlier. I'm thinking that the drawing code runs more often, so this
might help. Hard to say in advance though.

If it doesn't help, I can try grabbing the source colorspace :-)

[sail, 2013/01/04 23:51:33]

ok, sounds like best practice would be to create a bitmap with the destination
color space.

                      bytesPerRow:0
                     bitsPerPixel:0];
     [bmpImageRep setSize:size];
     [NSGraphicsContext setCurrentContext:
         [NSGraphicsContext graphicsContextWithBitmapImageRep:bmpImageRep]];
     drawingHandler(size);
     [result addRepresentation:bmpImageRep];
   }
   [NSGraphicsContext restoreGraphicsState];
 
@@ skipping 2046 matching lines @@
 NSView* GetSheetParentViewForWebContents(WebContents* web_contents) {
   // View hierarchy of the contents view:
   // NSView  -- switchView, same for all tabs
   // +- NSView  -- TabContentsController's view
   //    +- TabContentsViewCocoa
   //
   // Changing it? Do not forget to modify
   // -[TabStripController swapInTabAtIndex:] too.
   return [web_contents->GetNativeView() superview];
 }