Use 'GtkWidget' instead of '*' for default style rule.

It seems that wildcard '*' has higher precedenace than the base class in
style matching. Use 'GtkWidget' is better and we no longer have to explicitly
specify rules for dervied classes.

TEST=Verify omnibox edit's selection color is still right.

Change-Id: I320efcdcc8066883e859d29a164962bef6754363

Review URL:
1 file changed