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

chrome/browser/net/errorpage_browsertest.cc

Index: chrome/browser/net/errorpage_browsertest.cc
diff --git a/chrome/browser/net/errorpage_browsertest.cc b/chrome/browser/net/errorpage_browsertest.cc
index 7b7b29931cfcf2ab279c513d830e4e2b1a2bd653..21b7cf49685ecb819e80a878d936ae1df64b7f3a 100644
--- a/chrome/browser/net/errorpage_browsertest.cc
+++ b/chrome/browser/net/errorpage_browsertest.cc
@@ -18,6 +18,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/sequenced_worker_pool.h"
+#include "base/threading/thread_restrictions.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/browser/browsing_data/browsing_data_helper.h"
@@ -541,6 +542,7 @@ void InterceptNetworkTransactions(net::URLRequestContextGetter* getter,
 // button to launch a network diagnostics tool.
 IN_PROC_BROWSER_TEST_F(ErrorPageTest, FileNotFound) {
   // Create an empty temp directory, to be sure there's no file in it.
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
   base::ScopedTempDir temp_dir;
   ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
   GURL non_existent_file_url =