Darken Google logo less.

Sample screenshots:
https://screenshot.googleplex.com/H1mkRMhHjAT.png
https://screenshot.googleplex.com/eQpbkh9vQaO.png
https://screenshot.googleplex.com/3sfoZP8NaSa.png

Change-Id: I78cea0e8a387dcd3bc7aa1fe0396672e79fe7463
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1714219Reviewed-by: Kyle Milka <kmilka@chromium.org>
Commit-Queue: Gayane Petrosyan <gayane@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680104}

chrome/renderer/searchbox/searchbox_extension.cc

@@ -114,7 +114,7 @@ SkColor GetLogoColor(const ThemeBackgroundInfo& theme_info) {
                               !theme_info.custom_background_url.is_empty();
   if (theme_info.logo_alternate && !has_background_image) {
     logo_color = GetContrastingColorForBackground(theme_info.background_color,
-                                                  /*luminosity_change=*/0.4f);
+                                                  /*luminosity_change=*/0.3f);
   }
 
   return logo_color;