[Push] Enable PushManager.hasPermission() in browser tests.

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index c11062ceb34702f92dc7aaeacf8889e5064f2eb5..3b7d13b582e0b5b1434177dd0d0365048667165b 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -384,6 +384,10 @@ const char kEnablePreciseMemoryInfo[] = "enable-precise-memory-info";
 // Enables payloads for received push messages when using the W3C Push API.
 const char kEnablePushMessagePayload[] = "enable-push-message-payload";
 
+// Enable hasPermission() method of the W3C Push API.
+const char kEnablePushMessagingHasPermission[] =
+        "enable-push-messaging-has-permission";
+
 // Set options to cache V8 data. (off, preparse data, or code)
 const char kV8CacheOptions[] = "v8-cache-options";