[crankshaft] Support inlining of function calls in tail position (in ES6 sense).

src/crankshaft/lithium.cc

Index: src/crankshaft/lithium.cc
diff --git a/src/crankshaft/lithium.cc b/src/crankshaft/lithium.cc
index a1a73e4beb84042075fdf72be63a93ea8b170a06..3b25081f5527eb4bfe7fd2bd4c57c504b2252cbe 100644
--- a/src/crankshaft/lithium.cc
+++ b/src/crankshaft/lithium.cc
@@ -522,12 +522,28 @@ LEnvironment* LChunkBuilderBase::CreateEnvironment(
     ZoneList<HValue*>* objects_to_materialize) {
   if (hydrogen_env == NULL) return NULL;
 
+  BailoutId ast_id = hydrogen_env->ast_id();
+  DCHECK(!ast_id.IsNone() ||
+         (hydrogen_env->frame_type() != JS_FUNCTION &&
+          hydrogen_env->frame_type() != TAIL_CALLER_FUNCTION));
+
+  if (hydrogen_env->frame_type() == TAIL_CALLER_FUNCTION) {
+    // Skip potential outer arguments adaptor frame.
+    HEnvironment* outer_hydrogen_env = hydrogen_env->outer();
+    if (outer_hydrogen_env != nullptr &&
+        outer_hydrogen_env->frame_type() == ARGUMENTS_ADAPTOR) {
+      outer_hydrogen_env = outer_hydrogen_env->outer();
+    }
+    LEnvironment* outer = CreateEnvironment(
+        outer_hydrogen_env, argument_index_accumulator, objects_to_materialize);
+    return new (zone())
+        LEnvironment(hydrogen_env->closure(), hydrogen_env->frame_type(),
+                     ast_id, 0, 0, 0, outer, hydrogen_env->entry(), zone());
+  }
+
   LEnvironment* outer =
       CreateEnvironment(hydrogen_env->outer(), argument_index_accumulator,
                         objects_to_materialize);
-  BailoutId ast_id = hydrogen_env->ast_id();
-  DCHECK(!ast_id.IsNone() ||
-         hydrogen_env->frame_type() != JS_FUNCTION);
 
   int omitted_count = (hydrogen_env->frame_type() == JS_FUNCTION)
                           ? 0