color_utils cleanup:

chrome/browser/ui/views/download/download_item_view.cc

Index: chrome/browser/ui/views/download/download_item_view.cc
diff --git a/chrome/browser/ui/views/download/download_item_view.cc b/chrome/browser/ui/views/download/download_item_view.cc
index c14f2b9fdfd412c3785f45aabdd2a2a165f28f11..37e1d3fea903da22bfb59a386923ce55d51dadc6 100644
--- a/chrome/browser/ui/views/download/download_item_view.cc
+++ b/chrome/browser/ui/views/download/download_item_view.cc
@@ -61,45 +61,44 @@
 using content::DownloadItem;
 using extensions::ExperienceSamplingEvent;
 
+namespace {
+
 // TODO(paulg): These may need to be adjusted when download progress
 //              animation is added, and also possibly to take into account
 //              different screen resolutions.
-static const int kTextWidth = 140;            // Pixels
-static const int kDangerousTextWidth = 200;   // Pixels
-static const int kVerticalPadding = 3;        // Pixels
-static const int kVerticalTextPadding = 2;    // Pixels
-static const int kTooltipMaxWidth = 800;      // Pixels
+const int kTextWidth = 140;            // Pixels
+const int kDangerousTextWidth = 200;   // Pixels
+const int kVerticalPadding = 3;        // Pixels
+const int kVerticalTextPadding = 2;    // Pixels
+const int kTooltipMaxWidth = 800;      // Pixels
 
 // Padding around progress indicator, on all sides.
-static const int kProgressPadding = 7;
+const int kProgressPadding = 7;
 
 // We add some padding before the left image so that the progress animation icon
 // hides the corners of the left image.
-static const int kLeftPadding = 0;  // Pixels.
+const int kLeftPadding = 0;  // Pixels.
 
 // The space between the Save and Discard buttons when prompting for a dangerous
 // download.
-static const int kButtonPadding = 5;  // Pixels.
+const int kButtonPadding = 5;  // Pixels.
 
 // The space on the left and right side of the dangerous download label.
-static const int kLabelPadding = 4;  // Pixels.
+const int kLabelPadding = 4;  // Pixels.
 
-static const SkColor kFileNameDisabledColor = SkColorSetRGB(171, 192, 212);
+const SkColor kFileNameDisabledColor = SkColorSetRGB(171, 192, 212);
 
 // How long the 'download complete' animation should last for.
-static const int kCompleteAnimationDurationMs = 2500;
+const int kCompleteAnimationDurationMs = 2500;
 
 // How long the 'download interrupted' animation should last for.
-static const int kInterruptedAnimationDurationMs = 2500;
+const int kInterruptedAnimationDurationMs = 2500;
 
 // How long we keep the item disabled after the user clicked it to open the
 // downloaded item.
-static const int kDisabledOnOpenDuration = 3000;
+const int kDisabledOnOpenDuration = 3000;
 
-// Darken light-on-dark download status text by 20% before drawing, thus
-// creating a "muted" version of title text for both dark-on-light and
-// light-on-dark themes.
-static const double kDownloadItemLuminanceMod = 0.8;
+}  // namespace
 
 DownloadItemView::DownloadItemView(DownloadItem* download_item,
     DownloadShelfView* parent)
@@ -699,16 +698,12 @@ void DownloadItemView::OnPaintBackground(gfx::Canvas* canvas) {
               kVerticalTextPadding;
       SkColor file_name_color = GetThemeProvider()->GetColor(
           ThemeProperties::COLOR_BOOKMARK_TEXT);
-      // If text is light-on-dark, lightening it alone will do nothing.
-      // Therefore we mute luminance a wee bit before drawing in this case.
-      if (color_utils::RelativeLuminance(file_name_color) > 0.5)
-          file_name_color = SkColorSetRGB(
-              static_cast<int>(kDownloadItemLuminanceMod *
-                               SkColorGetR(file_name_color)),
-              static_cast<int>(kDownloadItemLuminanceMod *
-                               SkColorGetG(file_name_color)),
-              static_cast<int>(kDownloadItemLuminanceMod *
-                               SkColorGetB(file_name_color)));
+      // If text is light-on-dark, lightening it alone will do nothing.  In this
+      // case we multiply color components by 80% before drawing.
+      if (!color_utils::IsDark(file_name_color)) {

[Peter Kasting, 2016/03/04 01:39:26]

This is not the same as the old code.  IsDark() is based on luma, while
RelativeLuminance() has performed linearization.

These have fairly different results.  For example, when using "grey" colors (R =
G = B), !IsDark() will return true for everything (128, 128, 128) and higher,
while the old code would only return true for colors (188, 188, 188) and higher.

I suspect that the intent of the code was to do what I've changed it to.  We
would normally consider e.g. (160, 160, 160) to be "light" text. 
RelativeLuminance() is mostly of use when computing contrast ratios.

+        file_name_color =
+            color_utils::AlphaBlend(SK_ColorBLACK, file_name_color, 255 / 5);
+      }
       canvas->DrawStringRect(status_text_, font_list_, file_name_color,
                              gfx::Rect(mirrored_x, y, kTextWidth,
                                        font_list_.GetHeight()));