Use CreateAndOpenTemporaryFile for TestLauncher sub-process output.

CreateAndOpenTemporaryFile() both allocates a temporary-file name, and
opens the file, rather than having the launcher create the file, then
close and re-open it as we were doing previously.

Bug: 752557
Change-Id: Idd1122ae1688df4742103691176039faf6d3f136
Reviewed-on: https://chromium-review.googlesource.com/611775Reviewed-by: Paweł Hajdan Jr. <phajdan.jr@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495983}

base/test/launcher/test_launcher.cc

@@ -4,6 +4,8 @@
 
 #include "base/test/launcher/test_launcher.h"
 
+#include <stdio.h>
+
 #include <memory>
 
 #include "base/at_exit.h"
@@ -418,76 +420,65 @@ void DoLaunchChildTestProcess(
     const TestLauncher::GTestProcessLaunchedCallback& launched_callback) {
   TimeTicks start_time = TimeTicks::Now();
 
-  // Redirect child process output to a file.
-  FilePath output_file;
-  CHECK(CreateTemporaryFile(&output_file));
+  ScopedFILE output_file;
+  FilePath output_filename;
+  if (redirect_stdio) {
+    FILE* raw_output_file = CreateAndOpenTemporaryFile(&output_filename);
+    output_file.reset(raw_output_file);
+    CHECK(output_file);
+  }
 
   LaunchOptions options;
 #if defined(OS_WIN)
   options.inherit_mode = test_launch_options.inherit_mode;
   options.handles_to_inherit = test_launch_options.handles_to_inherit;
-
-  win::ScopedHandle handle;
-
   if (redirect_stdio) {
-    handle.Set(CreateFile(output_file.value().c_str(), GENERIC_WRITE,
-                          FILE_SHARE_READ | FILE_SHARE_DELETE, nullptr,
-                          OPEN_EXISTING, FILE_ATTRIBUTE_TEMPORARY, NULL));
-    CHECK(handle.IsValid());
+    HANDLE handle =
+        reinterpret_cast<HANDLE>(_get_osfhandle(_fileno(output_file.get())));
+    CHECK_NE(INVALID_HANDLE_VALUE, handle);
     options.stdin_handle = INVALID_HANDLE_VALUE;
-    options.stdout_handle = handle.Get();
-    options.stderr_handle = handle.Get();
+    options.stdout_handle = handle;
+    options.stderr_handle = handle;
     // See LaunchOptions.stdout_handle comments for why this compares against
     // FILE_TYPE_CHAR.
     if (options.inherit_mode == base::LaunchOptions::Inherit::kSpecific &&
-        GetFileType(handle.Get()) != FILE_TYPE_CHAR)
-      options.handles_to_inherit.push_back(handle.Get());
+        GetFileType(handle) != FILE_TYPE_CHAR) {
+      options.handles_to_inherit.push_back(handle);
+    }
   }
-
 #elif defined(OS_POSIX)
   options.new_process_group = true;
-#if defined(OS_LINUX)
-  options.kill_on_parent_death = true;
-#endif  // defined(OS_LINUX)
-
-  ScopedFD output_file_fd;
-
   options.fds_to_remap = test_launch_options.fds_to_remap;
   if (redirect_stdio) {
-    // Don't use O_CREATE here - CreateTemporaryFile should have created it.
-    // O_APPEND is necessary on Fuchsia, otherwise stdio/stderr will have
-    // independent seek positions, and trample one another (crbug.com/751253).
-    output_file_fd.reset(
-        open(output_file.value().c_str(), O_WRONLY | O_APPEND | O_TRUNC));
-    CHECK(output_file_fd.is_valid());
-
+    int output_file_fd = fileno(output_file.get());
+    CHECK_LE(0, output_file_fd);
     options.fds_to_remap.push_back(
-        std::make_pair(output_file_fd.get(), STDOUT_FILENO));
+        std::make_pair(output_file_fd, STDOUT_FILENO));
     options.fds_to_remap.push_back(
-        std::make_pair(output_file_fd.get(), STDERR_FILENO));
+        std::make_pair(output_file_fd, STDERR_FILENO));
   }
+
+#if defined(OS_LINUX)
+  options.kill_on_parent_death = true;
 #endif
 
+#endif  // defined(OS_POSIX)
+
   bool was_timeout = false;
   int exit_code = LaunchChildTestProcessWithOptions(
       command_line, options, test_launch_options.flags, timeout,
       launched_callback, &was_timeout);
 
-  if (redirect_stdio) {
-#if defined(OS_WIN)
-    FlushFileBuffers(handle.Get());
-    handle.Close();
-#elif defined(OS_POSIX)
-    output_file_fd.reset();
-#endif
-  }
-
   std::string output_file_contents;
-  CHECK(ReadFileToString(output_file, &output_file_contents));
+  if (redirect_stdio) {
+    fflush(output_file.get());
+    output_file.reset();
+    CHECK(ReadFileToString(output_filename, &output_file_contents));
 
-  if (!DeleteFile(output_file, false)) {
+    if (!DeleteFile(output_filename, false)) {
       // This needs to be non-fatal at least for Windows.
-    LOG(WARNING) << "Failed to delete " << output_file.AsUTF8Unsafe();
+      LOG(WARNING) << "Failed to delete " << output_filename.AsUTF8Unsafe();
+    }
   }
 
   // Run target callback on the thread it was originating from, not on