Visitor for checking that in each template, the parameters declared in the SoyDoc match the data keys referenced in the template.
Important: Do not use outside of Soy code (treat as superpackage-private).
Precondition: All template and callee names should be full names (i.e. you must execute {@code SetFullCalleeNamesVisitor} before executing this visitor).
Note this visitor only works for code in Soy V2 syntax.
{@link #exec} should be called on a full parse tree. There is no return value. However, a{@code SoySyntaxException} is thrown if the parameters declared in some template's SoyDoc do notmatch the data keys referenced in that template.
@author Kai Huang