[debugger] sunset --expose-debug-as flag.

R=jgruber@chromium.org
BUG=v8:5530

Review-Url: https://codereview.chromium.org/2589083002
Cr-Commit-Position: refs/heads/master@{#41832}

src/bootstrapper.cc

@@ -4076,25 +4076,6 @@ bool Genesis::InstallSpecialObjects(Handle<Context> native_context) {
   Handle<Smi> stack_trace_limit(Smi::FromInt(FLAG_stack_trace_limit), isolate);
   JSObject::AddProperty(Error, name, stack_trace_limit, NONE);
 
-  // Expose the debug global object in global if a name for it is specified.
-  if (FLAG_expose_debug_as != NULL && strlen(FLAG_expose_debug_as) != 0) {
-    // If loading fails we just bail out without installing the
-    // debugger but without tanking the whole context.
-    Debug* debug = isolate->debug();
-    if (!debug->Load()) return true;
-    Handle<Context> debug_context = debug->debug_context();
-    // Set the security token for the debugger context to the same as
-    // the shell native context to allow calling between these (otherwise
-    // exposing debug global object doesn't make much sense).
-    debug_context->set_security_token(native_context->security_token());
-    Handle<String> debug_string =
-        factory->InternalizeUtf8String(FLAG_expose_debug_as);
-    uint32_t index;
-    if (debug_string->AsArrayIndex(&index)) return true;
-    Handle<Object> global_proxy(debug_context->global_proxy(), isolate);
-    JSObject::AddProperty(global, debug_string, global_proxy, DONT_ENUM);
-  }
-
   WasmJs::Install(isolate, global);
 
   return true;

src/flag-definitions.h

@@ -600,7 +600,6 @@ DEFINE_BOOL(script_streaming, true, "enable parsing on background")
 
 // bootstrapper.cc
 DEFINE_STRING(expose_natives_as, NULL, "expose natives in global object")
-DEFINE_STRING(expose_debug_as, NULL, "expose debug in global object")
 DEFINE_BOOL(expose_free_buffer, false, "expose freeBuffer extension")
 DEFINE_BOOL(expose_gc, false, "expose gc extension")
 DEFINE_STRING(expose_gc_as, NULL,

test/cctest/compiler/test-run-bytecode-graph-builder.cc

@@ -3027,35 +3027,32 @@ TEST(BytecodeGraphBuilderIllegalConstDeclaration) {
   }
 }
 
+static int debug_break_count = 0;
+static void DebugEventCounter(const v8::Debug::EventDetails& event_details) {
+  if (event_details.GetEvent() == v8::Break) debug_break_count++;
+}
+
 TEST(BytecodeGraphBuilderDebuggerStatement) {
-  FLAG_expose_debug_as = "debug";
   HandleAndZoneScope scope;
   Isolate* isolate = scope.main_isolate();
   Zone* zone = scope.main_zone();
 
+  v8::Debug::SetDebugEventListener(CcTest::isolate(), DebugEventCounter);
+
   ExpectedSnippet<0> snippet = {
-      "var Debug = debug.Debug;"
-      "var count = 0;"
       "function f() {"
       "  debugger;"
       "}"
-      "function listener(event) {"
-      "  if (event == Debug.DebugEvent.Break) count++;"
-      "}"
-      "Debug.setListener(listener);"
-      "f();"
-      "Debug.setListener(null);"
-      "return count;",
-      {handle(Smi::FromInt(1), isolate)}};
-
-  ScopedVector<char> script(1024);
-  SNPrintF(script, "function %s() { %s }\n%s();", kFunctionName,
-           snippet.code_snippet, kFunctionName);
+      "f();",
+      {isolate->factory()->undefined_value()}};
 
-  BytecodeGraphTester tester(isolate, zone, script.start());
+  BytecodeGraphTester tester(isolate, zone, snippet.code_snippet);
   auto callable = tester.GetCallable<>();
   Handle<Object> return_value = callable().ToHandleChecked();
-  CHECK(return_value->SameValue(*snippet.return_value()));
+
+  v8::Debug::SetDebugEventListener(CcTest::isolate(), nullptr);
+  CHECK(return_value.is_identical_to(snippet.return_value()));
+  CHECK_EQ(2, debug_break_count);
 }
 
 }  // namespace compiler