provide a type for forward declared variable

Summary:
Recall that if another module exports a type (e.g. an interface),
tsickle will create a Closure @record variable from it in the other
module.  When this module imports that type, for Closure purposes
we need to declare a reference to the *value* of that record variable.

But at TS compilation time that @record doesn't yet exist, so we must
forward declare it using "declare".  This change gives that forward
declaration a type.  By the time Closure gets to compilations using
this variable, this declaration has entirely disappeared; it's just
to make the TS compiler happy in the interim.

More work on #112.

Reviewers: rkirov

Reviewed By: rkirov

Subscribers: typescript-eng

Differential Revision: https://reviews.angular.io/D153

Author: evmar

src/tsickle.ts

@@ -446,7 +446,7 @@ class Annotator extends Rewriter {
         if (!isValue) {
           // Once tsickle processes the other module, it will create a var for it.
           // But until then we just hack this symbol in to the value namespace.
-          this.emit(`declare var tsickle_${name};\n`);
+          this.emit(`declare var tsickle_${name}: any;\n`);
         }
         this.emit(`const ${name} = tsickle_${name};\n`);
         this.emit(`type ${name} = tsickle_${name};\n`);

test_files/jsdoc_types/jsdoc_types.tsickle.ts

@@ -17,7 +17,7 @@ const RenamedClassTwo = tsickle_RenamedClassTwo;
 type RenamedClassTwo = tsickle_RenamedClassTwo;
 
 import {Interface as tsickle_Interface,} from './module2';
-declare var tsickle_Interface;
+declare var tsickle_Interface: any;
 const Interface = tsickle_Interface;
 type Interface = tsickle_Interface;