Disable ExtensionsStartupTest.NoFileAccess on Mac.

chrome/browser/extensions/extension_startup_browsertest.cc

Index: chrome/browser/extensions/extension_startup_browsertest.cc
diff --git a/chrome/browser/extensions/extension_startup_browsertest.cc b/chrome/browser/extensions/extension_startup_browsertest.cc
index 7566caa8798a3dc66664ed2b252f15c59b4bd03d..0d056d0813ac6bc4cafba7b0b2b53815fc292ef9 100644
--- a/chrome/browser/extensions/extension_startup_browsertest.cc
+++ b/chrome/browser/extensions/extension_startup_browsertest.cc
@@ -144,9 +144,15 @@ IN_PROC_BROWSER_TEST_F(ExtensionsStartupTest, Test) {
   TestInjection(true, true);
 }
 
+// Sometimes times out on Mac.  http://crbug.com/48151
+#if defined(OS_MACOSX)
+#define MAYBE_NoFileAccess DISABLED_NoFileAccess
+#else
+#define MAYBE_NoFileAccess NoFileAccess
+#endif
 // Tests that disallowing file access on an extension prevents it from injecting
 // script into a page with a file URL.
-IN_PROC_BROWSER_TEST_F(ExtensionsStartupTest, NoFileAccess) {
+IN_PROC_BROWSER_TEST_F(ExtensionsStartupTest, MAYBE_NoFileAccess) {
   WaitForServicesToStart(4, true);  // 1 component extension and 3 others.
 
   ExtensionsService* service = browser()->profile()->GetExtensionsService();