Implement Mojo message codec in JavaScript

gin/test/file_runner.cc

Index: gin/test/file_runner.cc
diff --git a/gin/test/file_runner.cc b/gin/test/file_runner.cc
index a8d0cc213a66306f9e43b316d9eeb9f1baff3929..f80d4deae0a454d9fbdb3ddb98467d4991c4efe3 100644
--- a/gin/test/file_runner.cc
+++ b/gin/test/file_runner.cc
@@ -15,9 +15,14 @@ namespace gin {
 namespace {
 
 std::string GetExceptionInfo(const v8::TryCatch& try_catch) {
-  std::string info;
-  ConvertFromV8(try_catch.Message()->Get(), &info);
-  return info;
+  std::string message;
+  ConvertFromV8(try_catch.Message()->Get(), &message);
+
+  std::string source_line;
+  if (ConvertFromV8(try_catch.Message()->GetSourceLine(), &source_line))
+    message += "\n" + source_line;
+
+  return message;
 }
 
 }  // namespace
@@ -43,10 +48,7 @@ void FileRunnerDelegate::DidCreateContext(Runner* runner) {
                              GetGTestTemplate(runner->isolate()));
 }
 
-void RunTestFromFile(const base::FilePath& path, RunnerDelegate* delegate) {
-  ASSERT_TRUE(base::PathExists(path)) << path.LossyDisplayName();
-  std::string source;
-  ASSERT_TRUE(ReadFileToString(path, &source));
+void RunTestFromString(const std::string& source, RunnerDelegate* delegate) {
   gin::Runner runner(delegate, v8::Isolate::GetCurrent());
   gin::Runner::Scope scope(&runner);
 
@@ -61,4 +63,11 @@ void RunTestFromFile(const base::FilePath& path, RunnerDelegate* delegate) {
   EXPECT_EQ("PASS", result_string);
 }
 
+void RunTestFromFile(const base::FilePath& path, RunnerDelegate* delegate) {
+  ASSERT_TRUE(base::PathExists(path)) << path.LossyDisplayName();
+  std::string source;
+  ASSERT_TRUE(ReadFileToString(path, &source));
+  RunTestFromString(source, delegate);
+}
+
 }  // namespace gin