Fix integration tests in src/chrome and src/extensions so that we can turn on IO thread checks wi...

chrome/test/base/ui_test_utils.cc

Index: chrome/test/base/ui_test_utils.cc
diff --git a/chrome/test/base/ui_test_utils.cc b/chrome/test/base/ui_test_utils.cc
index d74c337f4d9ce254b1c761c016344f75a02ccdb5..dbfc6b7f1a185891cca97812b1d22427b21df6c0 100644
--- a/chrome/test/base/ui_test_utils.cc
+++ b/chrome/test/base/ui_test_utils.cc
@@ -19,6 +19,7 @@
 #include "base/path_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/test_timeouts.h"
+#include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
@@ -281,6 +282,7 @@ void NavigateToURLBlockUntilNavigationsComplete(Browser* browser,
 
 base::FilePath GetTestFilePath(const base::FilePath& dir,
                                const base::FilePath& file) {
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
   base::FilePath path;
   PathService::Get(chrome::DIR_TEST_DATA, &path);
   return path.Append(dir).Append(file);
@@ -291,6 +293,7 @@ GURL GetTestUrl(const base::FilePath& dir, const base::FilePath& file) {
 }
 
 bool GetRelativeBuildDirectory(base::FilePath* build_dir) {
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
   // This function is used to find the build directory so TestServer can serve
   // built files (nexes, etc).  TestServer expects a path relative to the source
   // root.
@@ -363,6 +366,7 @@ int FindInPage(WebContents* tab,
 }
 
 void DownloadURL(Browser* browser, const GURL& download_url) {
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
   base::ScopedTempDir downloads_directory;
   ASSERT_TRUE(downloads_directory.CreateUniqueTempDir());
   browser->profile()->GetPrefs()->SetFilePath(prefs::kDownloadDefaultDirectory,