[debugger] remove GeneratorMirror.prototype.context().

I can't express my disbelief when I saw it getting a raw context
object from the runtime. Luckily this is not used anywhere.

R=neis@chromium.org

Review URL: https://codereview.chromium.org/1844543002

Cr-Commit-Position: refs/heads/master@{#35102}

src/debug/mirrors.js

@@ -1434,14 +1434,6 @@ GeneratorMirror.prototype.func = function() {
 };
 
 
-GeneratorMirror.prototype.context = function() {
-  if (!this.context_) {
-    this.context_ = new ContextMirror(%GeneratorGetContext(this.value_));
-  }
-  return this.context_;
-};
-
-
 GeneratorMirror.prototype.receiver = function() {
   if (!this.receiver_) {
     this.receiver_ = MakeMirror(%GeneratorGetReceiver(this.value_));

src/runtime/runtime-generator.cc

@@ -148,16 +148,6 @@ RUNTIME_FUNCTION(Runtime_GeneratorGetFunction) {
 }
 
 
-// Returns context of generator activation.
-RUNTIME_FUNCTION(Runtime_GeneratorGetContext) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 1);
-  CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
-
-  return generator->context();
-}
-
-
 // Returns receiver of generator activation.
 RUNTIME_FUNCTION(Runtime_GeneratorGetReceiver) {
   HandleScope scope(isolate);

src/runtime/runtime.h

@@ -237,7 +237,6 @@ namespace internal {
   F(ResumeJSGeneratorObject, 3, 1)      \
   F(GeneratorClose, 1, 1)               \
   F(GeneratorGetFunction, 1, 1)         \
-  F(GeneratorGetContext, 1, 1)          \
   F(GeneratorGetReceiver, 1, 1)         \
   F(GeneratorGetInput, 1, 1)            \
   F(GeneratorGetContinuation, 1, 1)     \