When allowing an extension file:/// URL access, grant its process access to that scheme.

chrome/browser/extensions/cross_origin_xhr_apitest.cc

Index: chrome/browser/extensions/cross_origin_xhr_apitest.cc
diff --git a/chrome/browser/extensions/cross_origin_xhr_apitest.cc b/chrome/browser/extensions/cross_origin_xhr_apitest.cc
index 43fa2579070b5c5ec647ebe8e72a70490ef4aea7..7f678976e16ae4dce851dfd172c452a60584d476 100644
--- a/chrome/browser/extensions/cross_origin_xhr_apitest.cc
+++ b/chrome/browser/extensions/cross_origin_xhr_apitest.cc
@@ -17,9 +17,17 @@ IN_PROC_BROWSER_TEST_F(ExtensionApiTest, CrossOriginXHRAllURLs) {
   ASSERT_TRUE(RunExtensionTest("cross_origin_xhr/all_urls")) << message_;
 }
 
-// Flaky on the trybots. See http://crbug.com/96725.
-IN_PROC_BROWSER_TEST_F(ExtensionApiTest, FLAKY_CrossOriginXHRContentScript) {
+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, CrossOriginXHRContentScript) {
   host_resolver()->AddRule("*.com", "127.0.0.1");
   ASSERT_TRUE(StartTestServer());
   ASSERT_TRUE(RunExtensionTest("cross_origin_xhr/content_script")) << message_;
 }
+
+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, CrossOriginXHRFileAccess) {
+  ASSERT_TRUE(RunExtensionTest("cross_origin_xhr/file_access")) << message_;
+}
+
+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, CrossOriginXHRNoFileAccess) {
+  ASSERT_TRUE(RunExtensionTestNoFileAccess(
+      "cross_origin_xhr/no_file_access")) << message_;
+}