Support Function::SetName() with --harmony-function-tostring

This is used in chromium for html attribute event handlers.

See blink layout test fast/events/event-function-toString.html

Bug: v8:4958
Change-Id: Ib3d88af834bbb62b4ccd4683eda743d92064b075
Reviewed-on: https://chromium-review.googlesource.com/837641
Commit-Queue: Josh Wolfe <jwolfe@igalia.com>
Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50460}

src/objects.cc

@@ -13718,8 +13718,11 @@ Handle<Object> SharedFunctionInfo::GetSourceCodeHarmony(
       script_source, start_pos, shared->end_position());
   if (!shared->is_wrapped()) return source;
 
+  DCHECK(!shared->name_should_print_as_anonymous());
   IncrementalStringBuilder builder(isolate);
-  builder.AppendCString("function (");
+  builder.AppendCString("function ");
+  builder.AppendString(Handle<String>(shared->name(), isolate));
+  builder.AppendCString("(");
   Handle<FixedArray> args(Script::cast(shared->script())->wrapped_arguments());
   int argc = args->length();
   for (int i = 0; i < argc; i++) {

test/cctest/test-compiler.cc

@@ -727,6 +727,34 @@ void TestCompileFunctionInContextToStringImpl() {
           "}");
       CHECK(expected->Equals(env.local(), result).FromJust());
     }
+
+    // With a name:
+    {
+      v8::ScriptOrigin origin(v8_str("test"), v8_int(17), v8_int(31));
+      v8::ScriptCompiler::Source script_source(v8_str("return 0"), origin);
+
+      v8::TryCatch try_catch(CcTest::isolate());
+      v8::MaybeLocal<v8::Function> maybe_fun =
+          v8::ScriptCompiler::CompileFunctionInContext(
+              env.local(), &script_source, 0, nullptr, 0, nullptr);
+
+      CHECK_NOT_CAUGHT(env.local(), try_catch,
+                       "v8::ScriptCompiler::CompileFunctionInContext");
+
+      v8::Local<v8::Function> fun = maybe_fun.ToLocalChecked();
+      CHECK(!fun.IsEmpty());
+      CHECK(!try_catch.HasCaught());
+
+      fun->SetName(v8_str("onclick"));
+
+      v8::Local<v8::String> result =
+          fun->ToString(env.local()).ToLocalChecked();
+      v8::Local<v8::String> expected = v8_str(
+          "function onclick() {\n"
+          "return 0\n"
+          "}");
+      CHECK(expected->Equals(env.local(), result).FromJust());
+    }
   }
 #undef CHECK_NOT_CAUGHT
 }