how to inject javascript and modify native android browser google search results

i want to accomplish something like this software. http://www.siteadvisor.com/mobile/android/pc.html

write a plugin kind of a thing for the default android browser which place a small icon against each search results based on their category. When i installed their SiteAdvisor.apk software , looks like it runs as a service and does this modification whenever we do google search. I really do not know can i accomplish it. when i installed the SiteAdvisor.apk though adb i got the following logcat (attached). Any pointers on how it can be accomplished will be very helpful for me. I have just started android deve开发者_开发技巧lopment. so dont know much about it. just started learning.

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You can try to reverse engineer existing app