Disallow theme colors with luminance > 0.94

chrome/android/java/src/org/chromium/chrome/browser/util/ColorUtils.java

Index: chrome/android/java/src/org/chromium/chrome/browser/util/ColorUtils.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/util/ColorUtils.java b/chrome/android/java/src/org/chromium/chrome/browser/util/ColorUtils.java
index f2e71b8463c07868c59106bbf74d7fc112971c18..e0d9a68168fc21829d4c3325982b9cb35a0be00b 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/util/ColorUtils.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/util/ColorUtils.java
@@ -20,6 +20,7 @@ public class ColorUtils {
     private static final float CONTRAST_LIGHT_ITEM_THRESHOLD = 3f;
     private static final float LIGHTNESS_OPAQUE_BOX_THRESHOLD = 0.82f;
     private static final float LOCATION_BAR_TRANSPARENT_BACKGROUND_ALPHA = 0.2f;
+    private static final float MAX_LUMINANCE_FOR_VALID_THEME_COLOR = 0.94f;
 
     /** Percentage to darken a color by when setting the status bar color. */
     private static final float DARKEN_COLOR_FRACTION = 0.6f;
@@ -155,4 +156,13 @@ public class ColorUtils {
     public static boolean isUsingDefaultToolbarColor(Resources resources, int color) {
         return color == ApiCompatibilityUtils.getColor(resources, R.color.default_primary_color);
     }
+
+    /**
+     * Determine if a theme color is valid. A theme color is invalid if its luminance is > 0.94.
+     * @param color The color to test.
+     * @return True if the theme color is valid.
+     */
+    public static boolean isValidThemeColor(int color) {
+        return ColorUtils.getLightnessForColor(color) <= MAX_LUMINANCE_FOR_VALID_THEME_COLOR;
+    }
 }