fix(compiler): Only emit metadata for exported enums (#10957)

Closes: #10955

tools/@angular/tsc-wrapped/src/collector.ts

@@ -247,6 +247,7 @@ export class MetadataCollector {
           // Otherwise don't record the function.
           break;
         case ts.SyntaxKind.EnumDeclaration:
+          if (node.flags & ts.NodeFlags.Export) {
             const enumDeclaration = <ts.EnumDeclaration>node;
             let enumValueHolder: {[name: string]: MetadataValue} = {};
             const enumName = enumDeclaration.name.text;
@@ -285,6 +286,7 @@ export class MetadataCollector {
               if (!metadata) metadata = {};
               metadata[enumName] = enumValueHolder;
             }
+          }
           break;
         case ts.SyntaxKind.VariableStatement:
           const variableStatement = <ts.VariableStatement>node;

tools/@angular/tsc-wrapped/test/collector.spec.ts

@@ -25,6 +25,7 @@ describe('Collector', () => {
       'exported-enum.ts',
       'exported-consts.ts',
       'local-symbol-ref.ts',
+      'private-enum.ts',
       're-exports.ts',
       'static-field-reference.ts',
       'static-method.ts',
@@ -339,6 +340,15 @@ describe('Collector', () => {
     expect(someEnum).toEqual({A: 0, B: 1, C: 100, D: 101});
   });
 
+  it('should ignore a non-export enum', () => {
+    let enumSource = program.getSourceFile('/private-enum.ts');
+    let metadata = collector.getMetadata(enumSource);
+    let publicEnum: any = metadata.metadata['PublicEnum'];
+    let privateEnum: any = metadata.metadata['PrivateEnum'];
+    expect(publicEnum).toEqual({a: 0, b: 1, c: 2});
+    expect(privateEnum).toBeUndefined();
+  });
+
   it('should be able to collect enums initialized from consts', () => {
     let enumSource = program.getSourceFile('/exported-enum.ts');
     let metadata = collector.getMetadata(enumSource);
@@ -838,6 +848,10 @@ const FILES: Directory = {
     })
     export class SomeComponent {}
   `,
+  'private-enum.ts': `
+    export enum PublicEnum { a, b, c }
+    enum PrivateEnum { e, f, g }
+  `,
   'node_modules': {
     'angular2': {
       'core.d.ts': `