Bring back "Search by image" button

Before the recent changes, clicking the listed resolution of an images would result in a search for alternate sources of the image, listed by resolution.
It's still possible to get these results by copying the image URL, going to images.google.com choosing search by image, picking URL and pasting in the source you found.
With this (first result for an image search for "car") as an example URL: https://www.cstatic-images.com/stock/379x253/15/img-1276321340-1509471668915.jpg

This would be the search URL showing alternate sizes (Which doesn't look very helpful to me):
https://www.google.com/search?safe=off&hl=en&q=car&tbm=isch&tbs=simg:CAQSlwEJVyVSPBXpYsYaiwELEKjU2AQaBAgVCAgMCxCwjKcIGmIKYAgDEijzDfYN8g30Dd0E9Q3OBPEN-Q3fBMoyvTLhILwyyzLJMroywzK1P84yGjDoZ8pA9mX7Mcv7BXxuBq7OhozZf739GJrh9kmrbxrUZQ39zo7EXosNGWkgra33MnMgBAwLEI6u_1ggaCgoICAESBAUYHhsM&sa=X&ved=0ahUKEwiarKHB6KzZAhUD0WMKHfNcAmUQ2A4IJygB&biw=1920&bih=974

Reproduce the issue on Google Image Search using the example image-search and source URLs in the report. Start by locating the extension entry point that adds actions to image-search results, then compare the current result controls with the requested “Search by image” behavior. Done means the button is available on image results and opens alternate-source results for the selected image.

Written by the indexing model from the issue text.