In Safari the variable 'src' ends up being 'data:...' valued, while
script.baseURI would be usable, so let's add an if statement to just
use that. 'data:...' is not a suitable input for getPluginNameFromUrl().
Bug: Issue 11128
Change-Id: I83de47382d335cf67f0922c56f1b10a4b252e529