[builtins] Also migrate String.prototype.toLowerCase/toUpperCase to C++.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 096ee63b2e5243605a7b1d42405d79cf16874279..bdf379b7d709885e04dd1b4bfdd58ac1e58e04d8 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1340,6 +1340,17 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
                           1, true);
     SimpleInstallFunction(prototype, "charCodeAt",
                           Builtins::kStringPrototypeCharCodeAt, 1, true);
+    // TODO(bmeurer): One day we will want to install the correct i18n functions
+    // here directly instead of first installing the dummy, and overriding those
+    // in i18n.js later.
+    SimpleInstallFunction(prototype, "toLocaleLowerCase",
+                          Builtins::kStringPrototypeToLowerCase, 0, false);
+    SimpleInstallFunction(prototype, "toLocaleUpperCase",
+                          Builtins::kStringPrototypeToUpperCase, 0, false);
+    SimpleInstallFunction(prototype, "toLowerCase",
+                          Builtins::kStringPrototypeToLowerCase, 0, false);
+    SimpleInstallFunction(prototype, "toUpperCase",
+                          Builtins::kStringPrototypeToUpperCase, 0, false);
     SimpleInstallFunction(prototype, "trim", Builtins::kStringPrototypeTrim, 0,
                           false);
     SimpleInstallFunction(prototype, "trimLeft",