Let Custom Tabs Use Light Progressbar for Dark Toolbar

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 6276c5a4b957bc7809b9377b2d2269b702717859..f64e8b0a7a6289699f92859f1a43396cd40b0b7f 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
@@ -13,6 +13,7 @@ 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 LIGHT_PROGRESSBAR_BACKGROUND_ALPHA = 0.5f;
 
     /** Percentage to darken a color by when setting the status bar color. */
     private static final float DARKEN_COLOR_FRACTION = 0.6f;
@@ -52,6 +53,15 @@ public class ColorUtils {
         return getColorWithOverlay(Color.WHITE, color, LOCATION_BAR_TRANSPARENT_BACKGROUND_ALPHA);
     }
 
+    /**
+     * Gets the background color for light theme progress bar.
+     * @param toolbarColor The color of the toolbar.
+     * @return The color of the progress bar in light theme, given the toolbar color.
+     */
+    public static int getLightProgressbarBackground(int toolbarColor) {
+        return getColorWithOverlay(Color.WHITE, toolbarColor, LIGHT_PROGRESSBAR_BACKGROUND_ALPHA);
+    }
+
     private static int getColorWithOverlay(int baseColor, int overlayColor, float overlayAlpha) {
         return Color.rgb(
             (int) (overlayAlpha * Color.red(baseColor)