[builtins] Introduce proper Float64Atan and Float64Atan2 operators.

src/bootstrapper.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/code-stubs.h"
 #include "src/extensions/externalize-string-extension.h"
@@ skipping 1654 matching lines @@
     Handle<JSFunction> cons = factory->NewFunction(name);
     JSFunction::SetInstancePrototype(
         cons,
         Handle<Object>(native_context()->initial_object_prototype(), isolate));
     Handle<JSObject> math = factory->NewJSObject(cons, TENURED);
     DCHECK(math->IsJSObject());
     JSObject::AddProperty(global, name, math, DONT_ENUM);
     SimpleInstallFunction(math, "acos", Builtins::kMathAcos, 1, true);
     SimpleInstallFunction(math, "asin", Builtins::kMathAsin, 1, true);
     SimpleInstallFunction(math, "atan", Builtins::kMathAtan, 1, true);
+    SimpleInstallFunction(math, "atan2", Builtins::kMathAtan2, 2, true);
     SimpleInstallFunction(math, "ceil", Builtins::kMathCeil, 1, true);
     SimpleInstallFunction(math, "clz32", Builtins::kMathClz32, 1, true);
     Handle<JSFunction> math_floor =
         SimpleInstallFunction(math, "floor", Builtins::kMathFloor, 1, true);
     native_context()->set_math_floor(*math_floor);
     SimpleInstallFunction(math, "fround", Builtins::kMathFround, 1, true);
     SimpleInstallFunction(math, "imul", Builtins::kMathImul, 2, true);
     Handle<JSFunction> math_log =
         SimpleInstallFunction(math, "log", Builtins::kMathLog, 1, true);
     native_context()->set_math_log(*math_log);
@@ skipping 2248 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8