diff --git a/dom/base/nsJSEnvironment.cpp b/dom/base/nsJSEnvironment.cpp
index 54cc8187139..ff7528bff30 100644
--- a/dom/base/nsJSEnvironment.cpp
+++ b/dom/base/nsJSEnvironment.cpp
@@ -1593,14 +1593,16 @@ TraceMallocOpenLogFile(JSContext *cx, unsigned argc, JS::Value *vp)
 static bool
 TraceMallocChangeLogFD(JSContext *cx, unsigned argc, JS::Value *vp)
 {
+    JS::CallArgs args = CallArgsFromVp(argc, vp);
+
     if (!CheckUniversalXPConnectForTraceMalloc(cx))
         return false;
 
     int32_t fd, oldfd;
-    if (argc == 0) {
+    if (args.length() == 0) {
         oldfd = -1;
     } else {
-        if (!JS_ValueToECMAInt32(cx, JS_ARGV(cx, vp)[0], &fd))
+        if (!JS::ToInt32(cx, args[0], &fd))
             return false;
         oldfd = NS_TraceMallocChangeLogFD(fd);
         if (oldfd == -2) {
@@ -1608,23 +1610,27 @@ TraceMallocChangeLogFD(JSContext *cx, unsigned argc, JS::Value *vp)
             return false;
         }
     }
-    JS_SET_RVAL(cx, vp, INT_TO_JSVAL(oldfd));
+    args.rval().setInt32(oldfd);
     return true;
 }
 
 static bool
 TraceMallocCloseLogFD(JSContext *cx, unsigned argc, JS::Value *vp)
 {
+    JS::CallArgs args = CallArgsFromVp(argc, vp);
+
     if (!CheckUniversalXPConnectForTraceMalloc(cx))
         return false;
 
     int32_t fd;
-    JS_SET_RVAL(cx, vp, JSVAL_VOID);
-    if (argc == 0)
+    if (args.length() == 0) {
+        args.rval().setUndefined();
         return true;
-    if (!JS_ValueToECMAInt32(cx, JS_ARGV(cx, vp)[0], &fd))
+    }
+    if (!JS::ToInt32(cx, args[0], &fd))
         return false;
     NS_TraceMallocCloseLogFD((int) fd);
+    args.rval().setInt32(fd);
     return true;
 }
 
diff --git a/dom/base/nsJSTimeoutHandler.cpp b/dom/base/nsJSTimeoutHandler.cpp
index 14184775456..ad23ac605ff 100644
--- a/dom/base/nsJSTimeoutHandler.cpp
+++ b/dom/base/nsJSTimeoutHandler.cpp
@@ -191,11 +191,15 @@ nsJSScriptTimeoutHandler::Init(nsGlobalWindow *aWindow, bool *aIsInterval,
   }
 
   int32_t interval = 0;
-  if (argc > 1 && !::JS_ValueToECMAInt32(cx, argv[1], &interval)) {
-    ::JS_ReportError(cx,
-                     "Second argument to %s must be a millisecond interval",
-                     aIsInterval ? kSetIntervalStr : kSetTimeoutStr);
-    return NS_ERROR_DOM_TYPE_ERR;
+  if (argc > 1) {
+    JS::Rooted<JS::Value> arg(cx, argv[1]);
+
+    if (!JS::ToInt32(cx, arg, &interval)) {
+      ::JS_ReportError(cx,
+                       "Second argument to %s must be a millisecond interval",
+                       aIsInterval ? kSetIntervalStr : kSetTimeoutStr);
+      return NS_ERROR_DOM_TYPE_ERR;
+    }
   }
 
   if (argc == 1) {
diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index 7f9b69e5cce..e9c25e73717 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -271,6 +271,7 @@ JS_ConvertArgumentsVA(JSContext *cx, unsigned argc, jsval *argv, const char *for
             }
             break;
         }
+        RootedValue arg(cx, *sp);
         switch (c) {
           case 'b':
             *va_arg(ap, bool *) = ToBoolean(*sp);
@@ -280,7 +281,7 @@ JS_ConvertArgumentsVA(JSContext *cx, unsigned argc, jsval *argv, const char *for
                 return false;
             break;
           case 'i':
-            if (!JS_ValueToECMAInt32(cx, *sp, va_arg(ap, int32_t *)))
+            if (!ToInt32(cx, arg, va_arg(ap, int32_t *)))
                 return false;
             break;
           case 'u':
@@ -474,12 +475,6 @@ JS_DoubleToUint32(double d)
     return ToUint32(d);
 }
 
-JS_PUBLIC_API(bool)
-JS_ValueToECMAInt32(JSContext *cx, jsval valueArg, int32_t *ip)
-{
-    RootedValue value(cx, valueArg);
-    return JS::ToInt32(cx, value, ip);
-}
 
 JS_PUBLIC_API(bool)
 JS_ValueToECMAUint32(JSContext *cx, jsval valueArg, uint32_t *ip)
diff --git a/js/xpconnect/src/dictionary_helper_gen.py b/js/xpconnect/src/dictionary_helper_gen.py
index 50d85bab678..7f69b1472e9 100644
--- a/js/xpconnect/src/dictionary_helper_gen.py
+++ b/js/xpconnect/src/dictionary_helper_gen.py
@@ -293,12 +293,12 @@ def write_getter(a, iface, fd):
         fd.write("    aDict.%s = u;\n" % a.name)
     elif realtype.count("int16_t"):
         fd.write("    int32_t i;\n")
-        fd.write("    NS_ENSURE_STATE(JS_ValueToECMAInt32(aCx, v, &i));\n")
+        fd.write("    NS_ENSURE_STATE(JS::ToInt32(aCx, v, &i));\n")
         fd.write("    aDict.%s = i;\n" % a.name)
     elif realtype.count("uint32_t"):
         fd.write("    NS_ENSURE_STATE(JS_ValueToECMAUint32(aCx, v, &aDict.%s));\n" % a.name)
     elif realtype.count("int32_t"):
-        fd.write("    NS_ENSURE_STATE(JS_ValueToECMAInt32(aCx, v, &aDict.%s));\n" % a.name)
+        fd.write("    NS_ENSURE_STATE(JS::ToInt32(aCx, v, &aDict.%s));\n" % a.name)
     elif realtype.count("uint64_t"):
         fd.write("    NS_ENSURE_STATE(JS::ToUint64(aCx, v, &aDict.%s));\n" % a.name)
     elif realtype.count("int64_t"):
diff --git a/js/xpconnect/src/qsgen.py b/js/xpconnect/src/qsgen.py
index d219a71bafd..8706dc013b6 100644
--- a/js/xpconnect/src/qsgen.py
+++ b/js/xpconnect/src/qsgen.py
@@ -391,7 +391,7 @@ argumentUnboxingTemplates = {
 
     'short':
         "    int32_t ${name}_i32;\n"
-        "    if (!JS_ValueToECMAInt32(cx, ${argVal}, &${name}_i32))\n"
+        "    if (!JS::ToInt32(cx, ${argVal}, &${name}_i32))\n"
         "        return false;\n"
         "    int16_t ${name} = (int16_t) ${name}_i32;\n",
 
@@ -403,7 +403,7 @@ argumentUnboxingTemplates = {
 
     'long':
         "    int32_t ${name};\n"
-        "    if (!JS_ValueToECMAInt32(cx, ${argVal}, &${name}))\n"
+        "    if (!JS::ToInt32(cx, ${argVal}, &${name}))\n"
         "        return false;\n",
 
     'unsigned long':
diff --git a/toolkit/components/telemetry/Telemetry.cpp b/toolkit/components/telemetry/Telemetry.cpp
index bcdd09ccf34..0073caa8339 100644
--- a/toolkit/components/telemetry/Telemetry.cpp
+++ b/toolkit/components/telemetry/Telemetry.cpp
@@ -622,20 +622,19 @@ IsEmpty(const Histogram *h)
 bool
 JSHistogram_Add(JSContext *cx, unsigned argc, JS::Value *vp)
 {
-  if (!argc) {
+  JS::CallArgs args = CallArgsFromVp(argc, vp);
+  if (!args.length()) {
     JS_ReportError(cx, "Expected one argument");
     return false;
   }
 
-  JS::Value v = JS_ARGV(cx, vp)[0];
-
-  if (!(JSVAL_IS_NUMBER(v) || JSVAL_IS_BOOLEAN(v))) {
+  if (!(args[0].isNumber() || args[0].isBoolean())) {
     JS_ReportError(cx, "Not a number");
     return false;
   }
 
   int32_t value;
-  if (!JS_ValueToECMAInt32(cx, v, &value)) {
+  if (!JS::ToInt32(cx, args[0], &value)) {
     return false;
   }