Add option to specify application entry points to the closure compiler.

src/main/java/com/google/javascript/clutz/Options.java

@@ -41,6 +41,13 @@ public class Options {
       usage = "emits platform externs, instead of omitting them in favor of TS lib.d.ts")
   boolean emitPlatformExterns;
 
+  @Option(name = "--closure_entry_point",
+      usage = "only generate output for the given entry points to the program. Must be" +
+              " goog.provide'd symbols.",
+      metaVar = "ENTRYPOINT...",
+      handler = StringArrayOptionHandler.class)
+  List<String> entryPoints = new ArrayList<>();
+
   @Argument
   List<String> arguments = new ArrayList<>();
 
@@ -50,6 +57,10 @@ public CompilerOptions getCompilerOptions() {
     final CompilerOptions options = new CompilerOptions();
     options.setClosurePass(true);
 
+    if (!this.entryPoints.isEmpty()) {
+      options.setManageClosureDependencies(this.entryPoints);
+    }
+
     // All diagnostics are WARNINGs (or off) and thus ignored unless debug == true.
     // Only report issues (and fail for them) that are specifically causing problems for Clutz.
     // The idea is to not do a general sanity check of Closure code, just make sure Clutz works.

src/test/java/com/google/javascript/clutz/OptionsTest.java

@@ -41,6 +41,17 @@ public void testFilterSourcesDepgraphs() throws Exception {
     assertThat(opts.output).isEqualTo("output.d.ts");
   }
 
+  @Test
+  public void testClosureEntryPoint() throws Exception {
+    Options opts = new Options(new String[] {
+            "foo.js", "--closure_entry_point", "entryPoint", "--externs", "extern1.js", "extern2.js", "-o", "output.d.ts"
+    });
+    assertThat(opts.arguments).containsExactly("foo.js");
+    assertThat(opts.entryPoints).containsExactly("entryPoint");
+    assertThat(opts.externs).containsExactly("extern1.js", "extern2.js").inOrder();
+    assertThat(opts.output).isEqualTo("output.d.ts");
+  }
+
   @Test
   public void testHandleEmptyCommandLine() throws Exception {
     ByteArrayOutputStream out = new ByteArrayOutputStream();