Move chrome/common/extensions/background_info.h to src/extensions

extensions/common/switches.cc

Index: extensions/common/switches.cc
diff --git a/extensions/common/switches.cc b/extensions/common/switches.cc
index 674bb03e4e4edbd7bfc1203a96384c549c3e2f18..558a7dabfbeeff408f92ae6a4031cb17a037acc2 100644
--- a/extensions/common/switches.cc
+++ b/extensions/common/switches.cc
@@ -8,6 +8,9 @@ namespace extensions {
 
 namespace switches {
 
+// Allows non-https URL for background_page for hosted apps.
+const char kAllowHTTPBackgroundPage[]       = "allow-http-background-page";
+
 // Allows the browser to load extensions that lack a modern manifest when that
 // would otherwise be forbidden.
 const char kAllowLegacyExtensionManifests[] =