Make content_browsertests support restarts across a test.

content/shell/shell_browser_context.cc

Index: content/shell/shell_browser_context.cc
===================================================================
--- content/shell/shell_browser_context.cc	(revision 152131)
+++ content/shell/shell_browser_context.cc	(working copy)
@@ -41,12 +41,15 @@
 
 void ShellBrowserContext::InitWhileIOAllowed() {
   CommandLine* cmd_line = CommandLine::ForCurrentProcess();
-  if (cmd_line->HasSwitch(switches::kContentBrowserTest) ||
-      cmd_line->HasSwitch(switches::kDumpRenderTree)) {
+  if (cmd_line->HasSwitch(switches::kDumpRenderTree)) {
     CHECK(testing_path_.CreateUniqueTempDir());
     path_ = testing_path_.path();
     return;
   }
+  if (cmd_line->HasSwitch(switches::kContentShellDataPath)) {
+    path_ = cmd_line->GetSwitchValuePath(switches::kContentShellDataPath);
+    return;
+  }
 #if defined(OS_WIN)
   CHECK(PathService::Get(base::DIR_LOCAL_APP_DATA, &path_));
   path_ = path_.Append(std::wstring(L"content_shell"));