Negative Action Highlighted Instead Of Positive Action On Google Chrome App Installation

While Adding an app to google chrome browser from the google chrome app store, the display notification highlights on the "Cancel" button with bold text and blue outline.

The display notification should be highlighting a positive action instead. That's "Add App".

Why is the negative action highlighted even after the user is sure about adding the app to the browser and has clicked "Add To Chrome"?

In my opinion,"Add App" should be highlighted as it encourages the user to move ahead with installation. Highlighting a negative action brings in a small sense of ambiguity to the user while installing.