new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/lib/evalInFrame.js
@@ -0,0 +1,32 @@
+var evalInFrame = (function (global) {
+  var dbgGlobal = newGlobal();
+  var dbg = new dbgGlobal.Debugger();
+
+  return function evalInFrame(upCount, code) {
+    dbg.addDebuggee(global);
+
+    // Skip ourself.
+    var frame = dbg.getNewestFrame().older;
+    for (var i = 0; i < upCount; i++) {
+      if (!frame.older)
+        break;
+      frame = frame.older;
+    }
+
+    var completion = frame.eval(code);
+    if (completion.return) {
+      var v = completion.return;
+      if (typeof v === "object")
+        v = v.unsafeDereference();
+      return v;
+    }
+    if (completion.throw) {
+      var v = completion.throw;
+      if (typeof v === "object")
+        v = v.unsafeDereference();
+      throw v;
+    }
+    if (completion === null)
+      terminate();
+  };
+})(this);

--- a/js/src/jit-test/tests/auto-regress/bug765483.js
+++ b/js/src/jit-test/tests/auto-regress/bug765483.js
@@ -1,16 +1,15 @@
 // |jit-test| error:ReferenceError;
 
 // Binary: cache/js-dbg-64-de23a9fc29db-linux
 // Flags: --ion-eager
 //
 
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 var obj1 = {}, obj2 = {};
 obj2['b'+i] = 0;
 for (var k in obj2) {
   (function g() { evalInFrame(1, "assertStackIs(['eval-code', f, 'bound(f)', 'global-code'])", true); })();
 }
 for (var i = 0; i != array.length; ++i)
   array[i]();

--- a/js/src/jit-test/tests/auto-regress/bug800878.js
+++ b/js/src/jit-test/tests/auto-regress/bug800878.js
@@ -1,11 +1,13 @@
 // |jit-test| error:Error
 
 // Binary: cache/js-dbg-32-1301a72b1c39-linux
 // Flags: --ion-eager
 //
 
+load(libdir + "evalInFrame.js");
+
 [1,2,3,4,(':'),6,7,8].forEach(
     function(x) {
         assertEq(evalInFrame(0, ('^')), x);
     }
 );

--- a/js/src/jit-test/tests/basic/bug646968-7.js
+++ b/js/src/jit-test/tests/basic/bug646968-7.js
@@ -1,10 +1,9 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 function test(s) {
     eval(s);
     let (y = evalInFrame(0, '3'), x = x) {
 	assertEq(x, 5);
     }
 }
 test('var x = 5;');

--- a/js/src/jit-test/tests/basic/bug646968-8.js
+++ b/js/src/jit-test/tests/basic/bug646968-8.js
@@ -1,8 +1,7 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 var x = 5;
 let (x = eval("x++")) {
     assertEq(evalInFrame(0, "x"), 5);
 }
 assertEq(x, 6);

--- a/js/src/jit-test/tests/basic/eif-generator.js
+++ b/js/src/jit-test/tests/basic/eif-generator.js
@@ -1,12 +1,9 @@
-var global = newGlobal();
-var dbg = new global.Debugger(this);
-// Force dbg to observe all execution.
-dbg.onDebuggerStatement = function () {};
+load(libdir + "evalInFrame.js");
 
 function f() {
     let (x = 1) {
         while (true) {
             yield evalInFrame(0, "x");
             x++;
             let (y = 1) {
                 yield evalInFrame(0, "++y");

--- a/js/src/jit-test/tests/basic/testBug552248.js
+++ b/js/src/jit-test/tests/basic/testBug552248.js
@@ -1,12 +1,9 @@
-var global = newGlobal();
-var dbg = new global.Debugger(this);
-// Force dbg to observe all execution.
-dbg.onDebuggerStatement = function () {};
+load(libdir + "evalInFrame.js");
 
 var a = new Array();
 
 function i(save) {
     var x = 9;
     evalInFrame(0, "a.push(x)", save);
     evalInFrame(1, "a.push(z)", save);
     evalInFrame(2, "a.push(z)", save);

--- a/js/src/jit-test/tests/basic/testBug663789-2.js
+++ b/js/src/jit-test/tests/basic/testBug663789-2.js
@@ -1,7 +1,6 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 o = { toString:function() { return evalInFrame(1, "x") } }
 var x = 'C';
 var s = "aaaaaaaaaa".replace(/a/g, function() { var x = 'B'; return o });
 assertEq(s, "CCCCCCCCCC");

--- a/js/src/jit-test/tests/basic/testEvalInFrameEdgeCase.js
+++ b/js/src/jit-test/tests/basic/testEvalInFrameEdgeCase.js
@@ -1,10 +1,9 @@
-var global = newGlobal();
-var dbg = new global.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 function g() {
     var x = 100;
     return evalInFrame(2, "x");
 }
 function f() {
     var x = 42;
     return evalInFrame.call(null, 0, "g()");

--- a/js/src/jit-test/tests/jaeger/bug563000/eif-call-newvar.js
+++ b/js/src/jit-test/tests/jaeger/bug563000/eif-call-newvar.js
@@ -1,10 +1,9 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 function callee() {
   evalInFrame(1, "var x = 'success'");
 }
 function caller(code) {
   eval(code);
   callee();
   return x;

--- a/js/src/jit-test/tests/jaeger/bug563000/eif-call-typechange.js
+++ b/js/src/jit-test/tests/jaeger/bug563000/eif-call-typechange.js
@@ -1,10 +1,9 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 function callee() {
   evalInFrame(1, "x = 'success'");
 }
 function caller() {
   var x = ({ dana : "zuul" });
   callee();
   return x;

--- a/js/src/jit-test/tests/jaeger/bug563000/eif-call.js
+++ b/js/src/jit-test/tests/jaeger/bug563000/eif-call.js
@@ -1,10 +1,9 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 function callee() {
   evalInFrame(1, "x = 'success'");
 }
 function caller() {
   var x = "failure";
   callee();
   return x;

--- a/js/src/jit-test/tests/jaeger/bug563000/eif-getter-newvar.js
+++ b/js/src/jit-test/tests/jaeger/bug563000/eif-getter-newvar.js
@@ -1,10 +1,9 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 this.__defineGetter__("someProperty", function () { evalInFrame(1, "var x = 'success'"); });
 function caller(obj) {
   var x = 'ignominy';
   obj.someProperty;
   return x;
 }
 assertEq(caller(this), "success");

--- a/js/src/jit-test/tests/jaeger/bug563000/eif-getter-typechange.js
+++ b/js/src/jit-test/tests/jaeger/bug563000/eif-getter-typechange.js
@@ -1,10 +1,9 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 this.__defineGetter__("someProperty", function () { evalInFrame(1, "var x = 'success'"); });
 function caller(obj) {
   var x = ({ dana : 'zuul' });
   obj.someProperty;
   return x;
 }
 assertEq(caller(this), "success");

--- a/js/src/jit-test/tests/jaeger/bug563000/eif-getter.js
+++ b/js/src/jit-test/tests/jaeger/bug563000/eif-getter.js
@@ -1,10 +1,9 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 this.__defineGetter__("someProperty", function () { evalInFrame(1, "x = 'success'"); });
 function caller(obj) {
   var x = "failure";
   obj.someProperty;
   return x;
 }
 assertEq(caller(this), "success");

--- a/js/src/jit-test/tests/jaeger/bug563000/eif-global-newvar.js
+++ b/js/src/jit-test/tests/jaeger/bug563000/eif-global-newvar.js
@@ -1,8 +1,7 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
+load(libdir + "evalInFrame.js");
 
 function callee() {
   evalInFrame(1, "var x = 'success'");
 }
 callee();
 assertEq(x, "success");

--- a/js/src/jit-test/tests/jaeger/invokeSessionGuard.js
+++ b/js/src/jit-test/tests/jaeger/invokeSessionGuard.js
@@ -1,11 +1,8 @@
-var g = newGlobal();
-var dbg = new g.Debugger(this);
-// Force dbg to observe all execution.
-dbg.onDebuggerStatement = function () {};
+load(libdir + "evalInFrame.js");
 
 [1,2,3,4,5,6,7,8].forEach(
     function(x) {
         // evalInFrame means lightweight gets call obj
         assertEq(evalInFrame(0, "x"), x);
     }
 );

--- a/js/src/js.msg
+++ b/js/src/js.msg
@@ -85,17 +85,16 @@ MSG_DEF(JSMSG_INVALID_DESCRIPTOR,      0
 MSG_DEF(JSMSG_OBJECT_NOT_EXTENSIBLE,   1, JSEXN_TYPEERR, "{0} is not extensible")
 MSG_DEF(JSMSG_CANT_REDEFINE_PROP,      1, JSEXN_TYPEERR, "can't redefine non-configurable property '{0}'")
 MSG_DEF(JSMSG_CANT_APPEND_TO_ARRAY,    0, JSEXN_TYPEERR, "can't add elements past the end of an array if its length property is unwritable")
 MSG_DEF(JSMSG_CANT_REDEFINE_ARRAY_LENGTH, 0, JSEXN_TYPEERR, "can't redefine array length")
 MSG_DEF(JSMSG_CANT_DEFINE_PAST_ARRAY_LENGTH, 0, JSEXN_TYPEERR, "can't define array index property past the end of an array with non-writable length")
 MSG_DEF(JSMSG_BAD_GET_SET_FIELD,       1, JSEXN_TYPEERR, "property descriptor's {0} field is neither undefined nor a function")
 MSG_DEF(JSMSG_THROW_TYPE_ERROR,        0, JSEXN_TYPEERR, "'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them")
 MSG_DEF(JSMSG_NOT_EXPECTED_TYPE,       3, JSEXN_TYPEERR, "{0}: expected {1}, got {2}")
-MSG_DEF(JSMSG_NEED_DEBUG_MODE,         0, JSEXN_ERR, "function can be called only if a Debugger is observing all execution")
 MSG_DEF(JSMSG_NOT_ITERABLE,            1, JSEXN_TYPEERR, "{0} is not iterable")
 MSG_DEF(JSMSG_ALREADY_HAS_PRAGMA,      2, JSEXN_NONE, "{0} is being assigned a {1}, but already has one")
 MSG_DEF(JSMSG_NEXT_RETURNED_PRIMITIVE, 0, JSEXN_TYPEERR, "iterator.next() returned a non-object value")
 MSG_DEF(JSMSG_WRONG_VALUE,             2, JSEXN_ERR, "expected {0} but found {1}")
 MSG_DEF(JSMSG_SETPROTOTYPEOF_FAIL,     1, JSEXN_TYPEERR, "[[SetPrototypeOf]] failed on {0}")
 MSG_DEF(JSMSG_INVALID_ARG_TYPE,        3, JSEXN_TYPEERR, "Invalid type: {0} can't be a{1} {2}")
 MSG_DEF(JSMSG_TERMINATED,              1, JSEXN_ERR, "Script terminated by timeout at:\n{0}")
 

--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -2633,80 +2633,16 @@ EvalInContext(JSContext *cx, unsigned ar
     }
 
     if (!cx->compartment()->wrap(cx, args.rval()))
         return false;
 
     return true;
 }
 
-static bool
-EvalInFrame(JSContext *cx, unsigned argc, jsval *vp)
-{
-    CallArgs args = CallArgsFromVp(argc, vp);
-    if (!args.get(0).isInt32() || !args.get(1).isString()) {
-        JS_ReportError(cx, "Invalid arguments to evalInFrame");
-        return false;
-    }
-
-    uint32_t upCount = args[0].toInt32();
-    RootedString str(cx, args[1].toString());
-    bool saveCurrent = args.get(2).isBoolean() ? args[2].toBoolean() : false;
-
-    if (!cx->compartment()->debugObservesAllExecution()) {
-        JS_ReportErrorFlagsAndNumber(cx, JSREPORT_ERROR, js_GetErrorMessage,
-                                     nullptr, JSMSG_NEED_DEBUG_MODE);
-        return false;
-    }
-
-    /* Debug-mode currently disables Ion compilation. */
-    ScriptFrameIter fi(cx);
-    for (uint32_t i = 0; i < upCount; ++i, ++fi) {
-        ScriptFrameIter next(fi);
-        ++next;
-        if (next.done())
-            break;
-    }
-
-    AutoStableStringChars stableChars(cx);
-    if (!stableChars.initTwoByte(cx, str))
-        return JSTRAP_ERROR;
-
-    AbstractFramePtr frame = fi.abstractFramePtr();
-    RootedScript fpscript(cx, frame.script());
-
-    RootedObject scope(cx);
-    {
-        RootedObject scopeChain(cx, frame.scopeChain());
-        AutoCompartment ac(cx, scopeChain);
-        scope = GetDebugScopeForFrame(cx, frame, fi.pc());
-    }
-    Rooted<Env*> env(cx, scope);
-    if (!env)
-        return false;
-
-    if (!ComputeThis(cx, frame))
-        return false;
-    RootedValue thisv(cx, frame.thisValue());
-
-    AutoSaveFrameChain sfc(cx);
-    if (saveCurrent) {
-        if (!sfc.save())
-            return false;
-    }
-
-    bool ok;
-    {
-        AutoCompartment ac(cx, env);
-        ok = EvaluateInEnv(cx, env, thisv, frame, stableChars.twoByteRange(), fpscript->filename(),
-                           PCToLineNumber(fpscript, fi.pc()), args.rval());
-    }
-    return ok;
-}
-
 struct WorkerInput
 {
     JSRuntime *runtime;
     char16_t *chars;
     size_t length;
 
     WorkerInput(JSRuntime *runtime, char16_t *chars, size_t length)
       : runtime(runtime), chars(chars), length(length)
@@ -4409,21 +4345,16 @@ static const JSFunctionSpecWithHelp shel
 "  Get script line extent."),
 
     JS_FN_HELP("evalcx", EvalInContext, 1, 0,
 "evalcx(s[, o])",
 "  Evaluate s in optional sandbox object o.\n"
 "  if (s == '' && !o) return new o with eager standard classes\n"
 "  if (s == 'lazy' && !o) return new o with lazy standard classes"),
 
-    JS_FN_HELP("evalInFrame", EvalInFrame, 2, 0,
-"evalInFrame(n,str,save)",
-"  Evaluate 'str' in the nth up frame.\n"
-"  If 'save' (default false), save the frame chain."),
-
     JS_FN_HELP("evalInWorker", EvalInWorker, 1, 0,
 "evalInWorker(str)",
 "  Evaluate 'str' in a separate thread with its own runtime.\n"),
 
     JS_FN_HELP("shapeOf", ShapeOf, 1, 0,
 "shapeOf(obj)",
 "  Get the shape of obj (an implementation detail)."),