Put dark background on default favicon

  Bug: 5711037

The default favicon had a transparent background and was placed over
a white background, so it looked all white.

Change-Id: I3bee26e0b9b524e606191a6d66f11c1984ff310e
diff --git a/res/drawable-hdpi/app_web_browser_sm.png b/res/drawable-hdpi/app_web_browser_sm.png
index a3f75cc..62d5cc3 100644
--- a/res/drawable-hdpi/app_web_browser_sm.png
+++ b/res/drawable-hdpi/app_web_browser_sm.png
Binary files differ
diff --git a/res/drawable-mdpi/app_web_browser_sm.png b/res/drawable-mdpi/app_web_browser_sm.png
index 6ac62eb..0bbc682 100644
--- a/res/drawable-mdpi/app_web_browser_sm.png
+++ b/res/drawable-mdpi/app_web_browser_sm.png
Binary files differ
diff --git a/res/drawable-xhdpi/app_web_browser_sm.png b/res/drawable-xhdpi/app_web_browser_sm.png
index 501af7f..45a5f12 100644
--- a/res/drawable-xhdpi/app_web_browser_sm.png
+++ b/res/drawable-xhdpi/app_web_browser_sm.png
Binary files differ