Add appIconMask to notification API

ui/message_center/views/small_image_mask.cc

+// Copyright 2014 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 "ui/message_center/views/small_image_mask.h"
+
+#include "ui/gfx/image/image_skia_operations.h"
+
+// Take small_iamge as the alpha channel, mask it with the foreground,
+// then add the masked foreground on top of the background
+const gfx::ImageSkia GetMaskedSmallImage(const gfx::ImageSkia& small_image) {

[dewittj, 2014/06/16 18:09:55]

I would just move this into notification_view.cc inside an anonymous namespace,
since there is only one consumer.  Not worth a new file here.

[liyanhou, 2014/06/27 03:18:40]

Done.

+  int width = small_image.width();
+  int height = small_image.height();
+
+  // Background color grey
+  const gfx::ImageSkia background = CreateImage(width, height, 163, 163, 163);

[dewittj, 2014/06/16 18:09:55]

I would suggest you use an SkColor in these functions instead.  See
SkBitmap::eraseColor (in fact eraseRGB is deprecated anyway).

Also, any constants you use should be defined in message_center_style.h so that
they can be used in the Mac version as well.  Define them something like this:

const SkColor kSmallImageMaskForegraound = SkColor...
const SkColor kSmallImageMaskBackground = SkColorWHITE;

You'll see other examples in message_center_style.

[liyanhou, 2014/06/27 03:18:40]

Done.

+  // Foreground color white
+  const gfx::ImageSkia foreground = CreateImage(width, height, 255, 255, 255);
+  const gfx::ImageSkia masked_small_image =
+      gfx::ImageSkiaOperations::CreateMaskedImage(foreground, small_image);
+  return gfx::ImageSkiaOperations::CreateSuperimposedImage(background,
+                                                           masked_small_image);
+}
+
+const gfx::ImageSkia CreateImage(int width,
+                                 int height,
+                                 int red,
+                                 int green,
+                                 int blue) {
+  return gfx::ImageSkia::CreateFrom1xBitmap(
+      CreateBitmap(width, height, red, green, blue));
+}
+
+const SkBitmap CreateBitmap(int width,
+                            int height,
+                            int red,
+                            int green,
+                            int blue) {
+  SkBitmap bitmap;
+  bitmap.setConfig(SkBitmap::kARGB_8888_Config, width, height);
+  bitmap.allocPixels();
+  bitmap.eraseRGB(red, green, blue);
+  return bitmap;
+}