Add support for module-definition files to gn

tools/gn/ninja_binary_target_writer_unittest.cc

Index: tools/gn/ninja_binary_target_writer_unittest.cc
diff --git a/tools/gn/ninja_binary_target_writer_unittest.cc b/tools/gn/ninja_binary_target_writer_unittest.cc
index df5f5a7168d32989bcce0b1c39bee0b511c84a9e..f4e4065f3a63381a2653bdf9b29ebea22387f2a3 100644
--- a/tools/gn/ninja_binary_target_writer_unittest.cc
+++ b/tools/gn/ninja_binary_target_writer_unittest.cc
@@ -357,3 +357,42 @@ TEST(NinjaBinaryTargetWriter, SourceSetDataDeps) {
       "  output_extension = \n";
   EXPECT_EQ(final_expected, final_out.str());
 }
+
+TEST(NinjaBinaryTargetWriter, SharedLibraryModuleDefinitionFile) {
+  TestWithScope setup;
+  setup.build_settings()->SetBuildDir(SourceDir("//out/Debug/"));
+  setup.settings()->set_target_os(Settings::WIN);
+
+  Target shared_lib(setup.settings(), Label(SourceDir("//foo/"), "bar"));
+  shared_lib.set_output_type(Target::SHARED_LIBRARY);
+  shared_lib.SetToolchain(setup.toolchain());
+  shared_lib.sources().push_back(SourceFile("//foo/sources.cc"));
+  shared_lib.sources().push_back(SourceFile("//foo/bar.def"));
+
+  Err err;
+  ASSERT_TRUE(shared_lib.OnResolved(&err));
+
+  std::ostringstream out;
+  NinjaBinaryTargetWriter writer(&shared_lib, out);
+  writer.Run();
+
+  const char expected[] =
+      "defines =\n"
+      "include_dirs =\n"
+      "cflags =\n"
+      "cflags_c =\n"
+      "cflags_cc =\n"
+      "cflags_objc =\n"
+      "cflags_objcc =\n"
+      "root_out_dir = .\n"
+      "target_out_dir = obj/foo\n"
+      "target_output_name = libbar\n"
+      "\n"
+      "build obj/foo/libbar.sources.o: cxx ../../foo/sources.cc\n"
+      "\n"
+      "build ./libbar.so: solink obj/foo/libbar.sources.o | ../../foo/bar.def\n"
+      "  ldflags = /DEF:../../foo/bar.def\n"
+      "  libs =\n"
+      "  output_extension = .so\n";
+  EXPECT_EQ(expected, out.str());
+}