Make the favicons look visually the same after refreshing

ui/gfx/image/image_mac.mm

Index: ui/gfx/image/image_mac.mm
diff --git a/ui/gfx/image/image_mac.mm b/ui/gfx/image/image_mac.mm
index c79100c408592f48e0029fdf13b0c30553aea42d..6c139f38010ff38efab9f46f3345812c7275c461 100644
--- a/ui/gfx/image/image_mac.mm
+++ b/ui/gfx/image/image_mac.mm
@@ -48,7 +48,8 @@ scoped_refptr<base::RefCountedMemory> Get1xPNGBytesFromNSImage(
   return refcounted_bytes;
 }
 
-NSImage* NSImageFromPNG(const std::vector<gfx::ImagePNGRep>& image_png_reps) {
+NSImage* NSImageFromPNG(const std::vector<gfx::ImagePNGRep>& image_png_reps,
+                        CGColorSpaceRef color_space) {
   if (image_png_reps.empty()) {
     LOG(ERROR) << "Unable to decode PNG.";
     return GetErrorNSImage();
@@ -69,6 +70,26 @@ NSImage* NSImageFromPNG(const std::vector<gfx::ImagePNGRep>& image_png_reps) {
       return GetErrorNSImage();
     }
 
+    // PNGCodec ignores colorspace related ancillary chunks (sRGB, iCCP). Ignore
+    // colorspace information when decoding directly from PNG to an NSImage so
+    // that the conversions: PNG -> SkBitmap -> NSImage and PNG -> NSImage
+    // produce visually similar results.
+    CGColorSpaceModel color_space_model = CGColorSpaceGetModel(
+        [[ns_image_rep colorSpace] CGColorSpace]);
+    CGColorSpaceModel decoded_color_space_model =
+        CGColorSpaceGetModel(color_space);
+    if (color_space_model == decoded_color_space_model) {
+      scoped_nsobject<NSColorSpace> ns_color_space(
+          [[NSColorSpace alloc] initWithCGColorSpace: color_space]);

[Avi (use Gerrit), 2013/06/12 01:35:29]

drive by: no space after the colon

+      NSBitmapImageRep* ns_retagged_image_rep =
+          [ns_image_rep
+              bitmapImageRepByRetaggingWithColorSpace: ns_color_space];

[Avi (use Gerrit), 2013/06/12 01:35:29]

drive by: no space after the colon

+      if (ns_retagged_image_rep && ns_retagged_image_rep != ns_image_rep) {
+        [ns_retagged_image_rep retain];

[pkotwicz, 2013/06/12 01:26:19]

I am confused why I need to retain |ns_retagged_image_rep|. (I get a crash if I
do not retain it)

[Avi (use Gerrit), 2013/06/12 01:35:29]

It comes from -bitmapImageRepByRetaggingWithColorSpace:, so it is autoreleased,
which means it has an effective retain count of 0. ns_image_rep is a
scoped_nsobject, which assumes that you are giving it a retained object, and
when it goes out of scope it will release it. So if you don't retain
ns_retagged_image_rep here, it gets released when ns_image_rep goes out of
scope, and then is released again when the autorelease pool goes away and you
die.

Style-wise, move the retain into the line below:

ns_image_rep.reset([ns_retagged_image_rep retain]);

+        ns_image_rep.reset(ns_retagged_image_rep);
+      }
+    }
+
     if (!image.get()) {
       float scale = ui::GetScaleFactorScale(image_png_reps[i].scale_factor);
       NSSize image_size = NSMakeSize([ns_image_rep pixelsWide] / scale,