Revert 163860 "Show speech button for x-webkit-speech only if th..."

Reason for revert: Tests InputTagSpeechBrowserTest.GrammarAttribute and InputTagSpeechBrowserTest.TestBasicRecognition in the range 163857:163860. This CL is the most probable cause. 

> Show speech button for x-webkit-speech only if the field is editable and focused/hovered.
> 
> BUG=325496
> 
> Review URL: https://codereview.chromium.org/100793006

TBR=tkent@chromium.org

Review URL: https://codereview.chromium.org/115353004

git-svn-id: svn://svn.chromium.org/blink/trunk@163884 bbb929c8-8fbe-4397-9dbb-9b2b20218538