Wholesale move of debugger sources to content.

content/browser/debugger/manual_tests/debugger-execution-while-paused.html

 <script>
 function stepOne()
 {
     console.log(1);
 }
 
 function stepTwo()
 {
     alert("Test failed. The second button event still fired.");
 }
 </script>
 
 <p>To test, open the DevTools (Ctrl+Shift+I) and reload the page. Set a break point inside the stepOne() function.
 Now click the Step One button in the page. The breakpoint should be hit. While paused at the breakpoint
 click on the Step Two button. You should not see an alert dialog. Continue script.</p>
 <button onclick="stepOne()">Step One</button><br><br>
 <button onclick="stepTwo()">Step Two</button>