Added usage of ScreenContext in EulaScreen.

chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc

Index: chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc
diff --git a/chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc
index 14f7c78b85da73ee5e0e828e56460171ed359e43..a421236bf5104b837cf91ef4db2e75bcccc758b5 100644
--- a/chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/base_screen_handler.cc
@@ -85,6 +85,12 @@ void BaseScreenHandler::GetLocalizedStrings(base::DictionaryValue* dict) {
   GetAdditionalParameters(dict);
 }
 
+void BaseScreenHandler::RegisterMessages() {
+  AddPrefixedCallback("contextChanged",
+                      &BaseScreenHandler::HandleContextChanged);
+  DeclareJSCallbacks();
+}
+
 void BaseScreenHandler::GetAdditionalParameters(base::DictionaryValue* dict) {
 }
 
@@ -112,4 +118,10 @@ std::string BaseScreenHandler::FullMethodPath(const std::string& method) const {
   return js_screen_path_prefix_ + method;
 }
 
+void BaseScreenHandler::HandleContextChanged(
+    const base::DictionaryValue* diff) {
+  if (diff && base_screen_)
+    base_screen_->OnContextChanged(*diff);
+}
+
 }  // namespace chromeos