1 files changed, 40 insertions, 19 deletions

diff --git a/chrome/browser/gtk/gtk_theme_provider.cc b/chrome/browser/gtk/gtk_theme_provider.cc
index a9e331b..4a4075f 100644
--- a/chrome/browser/gtk/gtk_theme_provider.cc
+++ b/chrome/browser/gtk/gtk_theme_provider.cc
@@ -30,6 +30,17 @@ const skia::HSL kExactColor = { -1, -1, -1 };
 
 const skia::HSL kDefaultFrameShift = { -1, -1, 0.4 };
 
+// Minimum difference between the toolbar and the button color before we try a
+// different color.
+const double kMinimumLuminanceDifference = 0.1;
+
+// Converts a GdkColor to a SkColor.
+SkColor GdkToSkColor(GdkColor* color) {
+  return SkColorSetRGB(color->red >> 8,
+                       color->green >> 8,
+                       color->blue >> 8);
+}
+
 }  // namespace
 
 // static
@@ -175,7 +186,9 @@ void GtkThemeProvider::LoadGtkValues() {
 
   GdkColor frame_color = window_style->bg[GTK_STATE_SELECTED];
   GdkColor inactive_frame_color = window_style->bg[GTK_STATE_INSENSITIVE];
+  GdkColor toolbar_color = window_style->bg[GTK_STATE_NORMAL];
   GdkColor button_color = window_style->bg[GTK_STATE_SELECTED];
+  GdkColor label_color = label_style->text[GTK_STATE_NORMAL];
 
   GtkSettings* settings = gtk_settings_get_default();
   bool theme_has_frame_color = false;
@@ -205,28 +218,39 @@ void GtkThemeProvider::LoadGtkValues() {
     // color, change the luminosity of the frame color downwards to 80% of what
     // it currently is. This is in a futile attempt to match the default
     // metacity and xfwm themes.
-    SkColor shifted =
-        skia::HSLShift(SkColorSetRGB((frame_color.red >> 8),
-                                     (frame_color.green >> 8),
-                                     (frame_color.blue >> 8)),
-                       kDefaultFrameShift);
+    SkColor shifted = skia::HSLShift(GdkToSkColor(&frame_color),
+                                     kDefaultFrameShift);
     frame_color.pixel = 0;
     frame_color.red = SkColorGetR(shifted) * kSkiaToGDKMultiplier;
     frame_color.green = SkColorGetG(shifted) * kSkiaToGDKMultiplier;
     frame_color.blue = SkColorGetB(shifted) * kSkiaToGDKMultiplier;
   }
 
+  // By default, the button tint color is the background selection color. But
+  // this can be unreadable in some dark themes, so we set a minimum contrast
+  // between the button color and the toolbar color.
+  skia::HSL button_hsl;
+  skia::SkColorToHSL(GdkToSkColor(&button_color), button_hsl);
+  skia::HSL toolbar_hsl;
+  skia::SkColorToHSL(GdkToSkColor(&toolbar_color), toolbar_hsl);
+  double hsl_difference = fabs(button_hsl.l - toolbar_hsl.l);
+  if (hsl_difference <= kMinimumLuminanceDifference) {
+    // Not enough contrast. Try the text color instead.
+    skia::HSL label_hsl;
+    skia::SkColorToHSL(GdkToSkColor(&label_color), label_hsl);
+    double label_difference = fabs(label_hsl.l - toolbar_hsl.l);
+    if (label_difference >= kMinimumLuminanceDifference) {
+      button_color = label_color;
+    }
+  }
+
   SetThemeColorFromGtk(kColorFrame, &frame_color);
   // Skip COLOR_FRAME_INACTIVE and the incognito colors, as they will be
   // autogenerated from tints.
-  SetThemeColorFromGtk(kColorToolbar,
-                       &window_style->bg[GTK_STATE_NORMAL]);
-  SetThemeColorFromGtk(kColorTabText,
-                       &label_style->text[GTK_STATE_NORMAL]);
-  SetThemeColorFromGtk(kColorBackgroundTabText,
-                       &label_style->text[GTK_STATE_NORMAL]);
-  SetThemeColorFromGtk(kColorBookmarkText,
-                       &label_style->text[GTK_STATE_NORMAL]);
+  SetThemeColorFromGtk(kColorToolbar, &toolbar_color);
+  SetThemeColorFromGtk(kColorTabText, &label_color);
+  SetThemeColorFromGtk(kColorBackgroundTabText, &label_color);
+  SetThemeColorFromGtk(kColorBookmarkText, &label_color);
   SetThemeColorFromGtk(kColorControlBackground,
                        &window_style->bg[GTK_STATE_NORMAL]);
   SetThemeColorFromGtk(kColorButtonBackground,
@@ -257,17 +281,14 @@ void GtkThemeProvider::LoadGtkValues() {
 }
 
 void GtkThemeProvider::SetThemeColorFromGtk(const char* id, GdkColor* color) {
-  SetColor(id, SkColorSetRGB(color->red >> 8,
-                             color->green >> 8,
-                             color->blue >> 8));
+  SetColor(id, GdkToSkColor(color));
 }
 
 void GtkThemeProvider::SetThemeTintFromGtk(const char* id, GdkColor* color,
                                            const skia::HSL& default_tint) {
   skia::HSL hsl;
-  skia::SkColorToHSL(SkColorSetRGB((color->red >> 8),
-                                   (color->green >> 8),
-                                   (color->blue >> 8)), hsl);
+  skia::SkColorToHSL(GdkToSkColor(color), hsl);
+
   if (default_tint.s != -1)
     hsl.s = default_tint.s;