How to create a Drupal View of CiviCRM Activities with an edit link to the corresponding Webform?
There is no straight forward way to get the 'Edit Submission' link in the View of CiviCRM Activities. Below is a workaround where we extract the 'Edit Submission' link from activity details.

Prerequisites:


Views PHP module is installed
In your webform, you have enabled/ticked 'Include link to edit webform submission in activity details'



Steps:


In the View of CiviCRM Activities, add 'CiviCRM Activities: Details' as a field to the view and tick 'Exclude from display'
Add a new field 'Global: PHP' to the view, and paste the below content in Output code 



&lt;?php
preg_match_all('/&lt;a href=\"([^\"]*)\"&gt;Edit Submission&lt;\/a&gt;/iU', $row-&gt;details, $match);
echo $match[0][0];
?&gt;



The above code will get the edit submission link from the activity details using regular expression and will display the link in the view.

View Final Output:


Hope this helps.