Make content_browsertests support restarts across a test.

content/public/test/test_launcher.cc

Index: content/public/test/test_launcher.cc
===================================================================
--- content/public/test/test_launcher.cc	(revision 152131)
+++ content/public/test/test_launcher.cc	(working copy)
@@ -440,9 +440,18 @@
   // failure status back to the parent.
   new_cmd_line.AppendSwitch(base::TestSuite::kStrictFailureHandling);
 
-  if (!launcher_delegate->AdjustChildProcessCommandLine(&new_cmd_line))
+  ScopedTempDir temp_dir;
+  // Create a new data dir and pass it to the child.
+  if (!temp_dir.CreateUniqueTempDir() || !temp_dir.IsValid()) {
+    LOG(ERROR) << "Error creating temp data directory";
     return -1;
+  }
 
+  if (!launcher_delegate->AdjustChildProcessCommandLine(&new_cmd_line,
+                                                        temp_dir.path())) {
+    return -1;
+  }
+
   return RunTestInternal(
       test_case, test_name, &new_cmd_line, default_timeout, was_timeout);
 }