Add support for writing system traces at startup

content/browser/tracing/trace_subscriber_stdio_unittest.cc

Index: content/browser/tracing/trace_subscriber_stdio_unittest.cc
diff --git a/content/browser/tracing/trace_subscriber_stdio_unittest.cc b/content/browser/tracing/trace_subscriber_stdio_unittest.cc
index 0b0e7c2ee800f40515ae153c48ec6ee0cb2c8a1a..6cb2632d3f152cd305b52d064d2b267ed2210bc9 100644
--- a/content/browser/tracing/trace_subscriber_stdio_unittest.cc
+++ b/content/browser/tracing/trace_subscriber_stdio_unittest.cc
@@ -14,12 +14,14 @@ namespace content {
 
 class TraceSubscriberStdioTest : public ::testing::Test {};
 
-TEST_F(TraceSubscriberStdioTest, CanWriteDataToFile) {
+TEST_F(TraceSubscriberStdioTest, CanWriteArray) {
   base::ScopedTempDir trace_dir;
   ASSERT_TRUE(trace_dir.CreateUniqueTempDir());
   base::FilePath trace_file(trace_dir.path().AppendASCII("trace.txt"));
   {
-    TraceSubscriberStdio subscriber(trace_file);
+    TraceSubscriberStdio subscriber(trace_file,
+                                    TraceSubscriberStdio::FILE_TYPE_ARRAY,
+                                    false);
 
     std::string foo("foo");
     subscriber.OnTraceDataCollected(
@@ -37,4 +39,92 @@ TEST_F(TraceSubscriberStdioTest, CanWriteDataToFile) {
   EXPECT_EQ("[foo,bar]", result);
 }
 
+TEST_F(TraceSubscriberStdioTest, CanWritePropertyList) {
+  base::ScopedTempDir trace_dir;
+  ASSERT_TRUE(trace_dir.CreateUniqueTempDir());
+  base::FilePath trace_file(trace_dir.path().AppendASCII("trace.txt"));
+  {
+    TraceSubscriberStdio subscriber(
+        trace_file,
+        TraceSubscriberStdio::FILE_TYPE_PROPERTY_LIST,
+        false);
+
+    std::string foo("foo");
+    subscriber.OnTraceDataCollected(
+        make_scoped_refptr(base::RefCountedString::TakeString(&foo)));
+
+    std::string bar("bar");
+    subscriber.OnTraceDataCollected(
+        make_scoped_refptr(base::RefCountedString::TakeString(&bar)));
+
+    subscriber.OnEndTracingComplete();
+  }
+  BrowserThread::GetBlockingPool()->FlushForTesting();
+  std::string result;
+  EXPECT_TRUE(file_util::ReadFileToString(trace_file, &result));
+  EXPECT_EQ("{\"traceEvents\":[foo,bar]}", result);
+}
+
+TEST_F(TraceSubscriberStdioTest, CanWriteSystemDataFirst) {
+  base::ScopedTempDir trace_dir;
+  ASSERT_TRUE(trace_dir.CreateUniqueTempDir());
+  base::FilePath trace_file(trace_dir.path().AppendASCII("trace.txt"));
+  {
+    TraceSubscriberStdio subscriber(
+        trace_file,
+        TraceSubscriberStdio::FILE_TYPE_PROPERTY_LIST,
+        true);
+
+    std::string foo("foo");
+    subscriber.OnTraceDataCollected(
+        make_scoped_refptr(base::RefCountedString::TakeString(&foo)));
+
+    std::string bar("bar");
+    subscriber.OnTraceDataCollected(
+        make_scoped_refptr(base::RefCountedString::TakeString(&bar)));
+
+    std::string systemTrace("event1\nevent2\n");
+    subscriber.OnEndSystemTracing(
+        make_scoped_refptr(base::RefCountedString::TakeString(&systemTrace)));
+    subscriber.OnEndTracingComplete();
+  }
+  BrowserThread::GetBlockingPool()->FlushForTesting();
+  std::string result;
+  EXPECT_TRUE(file_util::ReadFileToString(trace_file, &result));
+  EXPECT_EQ(
+    "{\"traceEvents\":[foo,bar],\"systemTraceEvents\":\"event1\\nevent2\\n\"}",
+    result);
+}
+
+TEST_F(TraceSubscriberStdioTest, CanWriteSystemDataLast) {
+  base::ScopedTempDir trace_dir;
+  ASSERT_TRUE(trace_dir.CreateUniqueTempDir());
+  base::FilePath trace_file(trace_dir.path().AppendASCII("trace.txt"));
+  {
+    TraceSubscriberStdio subscriber(
+        trace_file,
+        TraceSubscriberStdio::FILE_TYPE_PROPERTY_LIST,
+        true);
+
+    std::string foo("foo");
+    subscriber.OnTraceDataCollected(
+        make_scoped_refptr(base::RefCountedString::TakeString(&foo)));
+
+    std::string bar("bar");
+    subscriber.OnTraceDataCollected(
+        make_scoped_refptr(base::RefCountedString::TakeString(&bar)));
+
+    std::string systemTrace("event1\nevent2\n");
+    subscriber.OnEndTracingComplete();
+    subscriber.OnEndSystemTracing(
+        make_scoped_refptr(base::RefCountedString::TakeString(&systemTrace)));
+  }
+  BrowserThread::GetBlockingPool()->FlushForTesting();
+  std::string result;
+  EXPECT_TRUE(file_util::ReadFileToString(trace_file, &result));
+  EXPECT_EQ(
+    "{\"traceEvents\":[foo,bar],\"systemTraceEvents\":\"event1\\nevent2\\n\"}",
+    result);
+}
+
 }  // namespace content