[Mac] Desaturate the Favicon for Network Errors

chrome/browser/ui/cocoa/tab_contents/favicon_util_mac.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.
 
 #include "chrome/browser/ui/cocoa/tab_contents/favicon_util_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
+#include "base/mac/mac_util.h"
 #include "base/mac/scoped_nsobject.h"
 #include "components/favicon/content/content_favicon_driver.h"
+#include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/navigation_entry.h"
 #include "skia/ext/skia_utils_mac.h"
 #include "ui/base/material_design/material_design_controller.h"
 #include "ui/base/resource/resource_bundle.h"
+#include "ui/gfx/image/image_skia_operations.h"
 #include "ui/gfx/image/image_skia_util_mac.h"
 #include "ui/gfx/paint_vector_icon.h"
 #include "ui/gfx/vector_icons_public.h"
 #include "ui/resources/grit/ui_resources.h"
 
 namespace {
 
 const CGFloat kVectorIconSize = 16;
 
+// Desaturate favicon HSL shift values.
+const double kDesaturateHue = -1.0;
+const double kDesaturateSaturation = 0.0;
+const double kDesaturateLightness = 0.6;
+
 }  // namespace
 
 namespace mac {
 
 NSImage* FaviconForWebContents(content::WebContents* contents, SkColor color) {
   favicon::FaviconDriver* favicon_driver =
       contents ? favicon::ContentFaviconDriver::FromWebContents(contents)
                : nullptr;
   if (favicon_driver && favicon_driver->FaviconIsValid()) {
-    NSImage* image = favicon_driver->GetFavicon().AsNSImage();
+    gfx::Image favicon = favicon_driver->GetFavicon();
+    NSImage* image = nil;
+
+    // Check if there's a network error. If there is, desaturate the favicon.
+    content::NavigationEntry* entry =
+        contents->GetController().GetLastCommittedEntry();
+    if (entry && (entry->GetPageType() == content::PAGE_TYPE_ERROR)) {
+      const gfx::ImageSkia* image_skia = favicon.ToImageSkia();
+      if (image_skia) {
+        color_utils::HSL shift = {kDesaturateHue, kDesaturateSaturation,
+                                  kDesaturateLightness};
+        gfx::ImageSkia desaturated_favicon =
+            gfx::ImageSkiaOperations::CreateHSLShiftedImage(*image_skia, shift);

[Nico, 2016/09/08 20:54:12]

it feels like this should be code that's shared between ports (a function that
takes a naventry and a page type, and that returns the gfx::ImageSkia to use)

+        image = gfx::NSImageFromImageSkiaWithColorSpace(
+            desaturated_favicon, base::mac::GetSRGBColorSpace());
+      }
+    } else {
+      image = favicon.ToNSImage();
+    }
+
     // The |image| could be nil if the bitmap is null. In that case, fallback
     // to the default image.
-    if (image) {
+    if (image)
       return image;
-    }
   }
 
   if (ui::MaterialDesignController::IsModeMaterial()) {
     return NSImageFromImageSkia(gfx::CreateVectorIcon(
         gfx::VectorIconId::DEFAULT_FAVICON, kVectorIconSize, color));
   }
 
   ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   return rb.GetNativeImageNamed(IDR_DEFAULT_FAVICON).ToNSImage();
 }
 
 }  // namespace mac