deps: cherry-pick 50f7455 from upstream V8

Original commit message:

    [inspector] added Runtime.globalLexicalScopeNames method

    The method returns names for all available top-level scope variables
    in giving context.

    R=dgozman@chromium.org,jgruber@chromium.org

    Bug: chromium:681333
    Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
    Change-Id: I2d0b600e1afbfef9087f53ea9c26abe1e112047c
    Reviewed-on: https://chromium-review.googlesource.com/719409
    Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
    Reviewed-by: Yang Guo <yangguo@chromium.org>
    Reviewed-by: Jakob Gruber <jgruber@chromium.org>
    Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#48618}

Refs: 50f7455cd9

PR-URL: https://github.com/nodejs/node/pull/16591
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

common.gypi

@@ -27,7 +27,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.3',
+    'v8_embedder_string': '-node.4',
 
     # Enable disassembler for `--print-code` v8 options
     'v8_enable_disassembler': 1,

deps/v8/src/api.cc

@@ -10172,6 +10172,25 @@ void debug::QueryObjects(v8::Local<v8::Context> v8_context,
                                          predicate, objects);
 }
 
+void debug::GlobalLexicalScopeNames(
+    v8::Local<v8::Context> v8_context,
+    v8::PersistentValueVector<v8::String>* names) {
+  i::Handle<i::Context> context = Utils::OpenHandle(*v8_context);
+  i::Handle<i::ScriptContextTable> table(
+      context->global_object()->native_context()->script_context_table());
+  for (int i = 0; i < table->used(); i++) {
+    i::Handle<i::Context> context = i::ScriptContextTable::GetContext(table, i);
+    DCHECK(context->IsScriptContext());
+    i::Handle<i::ScopeInfo> scope_info(context->scope_info());
+    int local_count = scope_info->ContextLocalCount();
+    for (int j = 0; j < local_count; ++j) {
+      i::String* name = scope_info->ContextLocalName(j);
+      if (i::ScopeInfo::VariableIsSynthetic(name)) continue;
+      names->Append(Utils::ToLocal(handle(name)));
+    }
+  }
+}
+
 Local<String> CpuProfileNode::GetFunctionName() const {
   const i::ProfileNode* node = reinterpret_cast<const i::ProfileNode*>(this);
   i::Isolate* isolate = node->isolate();

deps/v8/src/debug/debug-interface.h

@@ -482,6 +482,9 @@ void QueryObjects(v8::Local<v8::Context> context,
                   QueryObjectPredicate* predicate,
                   v8::PersistentValueVector<v8::Object>* objects);
 
+void GlobalLexicalScopeNames(v8::Local<v8::Context> context,
+                             v8::PersistentValueVector<v8::String>* names);
+
 }  // namespace debug
 }  // namespace v8
 

deps/v8/src/inspector/js_protocol.json

@@ -355,6 +355,17 @@
                     { "name": "objects", "$ref": "RemoteObject", "description": "Array with objects." }
                 ],
                 "experimental": true
+            },
+            {
+                "name": "globalLexicalScopeNames",
+                "parameters": [
+                    { "name": "executionContextId", "$ref": "ExecutionContextId", "optional": true, "description": "Specifies in which execution context to lookup global scope variables." }
+                ],
+                "returns": [
+                    { "name": "names", "type": "array", "items": { "type": "string" } }
+                ],
+                "description": "Returns all let, const and class variables from global scope.",
+                "experimental": true
             }
         ],
         "events": [

deps/v8/src/inspector/v8-runtime-agent-impl.cc

@@ -586,6 +586,27 @@ Response V8RuntimeAgentImpl::queryObjects(
       resultArray, scope.objectGroupName(), false, false, objects);
 }
 
+Response V8RuntimeAgentImpl::globalLexicalScopeNames(
+    Maybe<int> executionContextId,
+    std::unique_ptr<protocol::Array<String16>>* outNames) {
+  int contextId = 0;
+  Response response = ensureContext(m_inspector, m_session->contextGroupId(),
+                                    std::move(executionContextId), &contextId);
+  if (!response.isSuccess()) return response;
+
+  InjectedScript::ContextScope scope(m_session, contextId);
+  response = scope.initialize();
+  if (!response.isSuccess()) return response;
+
+  v8::PersistentValueVector<v8::String> names(m_inspector->isolate());
+  v8::debug::GlobalLexicalScopeNames(scope.context(), &names);
+  *outNames = protocol::Array<String16>::create();
+  for (size_t i = 0; i < names.Size(); ++i) {
+    (*outNames)->addItem(toProtocolString(names.Get(i)));
+  }
+  return Response::OK();
+}
+
 void V8RuntimeAgentImpl::restore() {
   if (!m_state->booleanProperty(V8RuntimeAgentImplState::runtimeEnabled, false))
     return;

deps/v8/src/inspector/v8-runtime-agent-impl.h

@@ -101,6 +101,9 @@ class V8RuntimeAgentImpl : public protocol::Runtime::Backend {
   Response queryObjects(
       const String16& prototypeObjectId,
       std::unique_ptr<protocol::Runtime::RemoteObject>* objects) override;
+  Response globalLexicalScopeNames(
+      Maybe<int> executionContextId,
+      std::unique_ptr<protocol::Array<String16>>* outNames) override;
 
   void reset();
   void reportExecutionContextCreated(InspectedContext*);

deps/v8/test/inspector/runtime/runtime-global-lexical-scope-names-expected.txt

@@ -0,0 +1,64 @@
+Test for Runtime.globalLexicalScopeVariablesNames
+Running 'let a = 1'
+Values:
+a = 1
+
+Running 'let b = 2'
+Values:
+a = 1
+b = 2
+
+Running 'let b = 3'
+Values:
+a = 1
+b = 2
+
+Running 'const c = 4'
+Values:
+a = 1
+b = 2
+c = 4
+
+Running 'var d = 5'
+(should not be in list of scoped variables)
+Values:
+a = 1
+b = 2
+c = 4
+
+Running 'class Foo{}'
+Values:
+a = 1
+b = 2
+c = 4
+Foo =
+{
+    className : Function
+    description : class Foo{}
+    objectId : <objectId>
+    type : function
+}
+
+Adding script with scope variables
+Values:
+a = 1
+b = 2
+c = 4
+Foo =
+{
+    className : Function
+    description : class Foo{}
+    objectId : <objectId>
+    type : function
+}
+e = 1
+f = 2
+g = 3
+Boo =
+{
+    className : Function
+    description : class Boo {}
+    objectId : <objectId>
+    type : function
+}
+

deps/v8/test/inspector/runtime/runtime-global-lexical-scope-names.js

@@ -0,0 +1,59 @@
+// Copyright 2017 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.
+
+let {session, contextGroup, Protocol} =
+    InspectorTest.start('Test for Runtime.globalLexicalScopeVariablesNames');
+
+(async function test() {
+  InspectorTest.log('Running \'let a = 1\'');
+  Protocol.Runtime.evaluate({expression: 'let a = 1'});
+  await dumpGlobalScopeVariables();
+
+  InspectorTest.log('Running \'let b = 2\'');
+  Protocol.Runtime.evaluate({expression: 'let b = 2'});
+  await dumpGlobalScopeVariables();
+
+  InspectorTest.log('Running \'let b = 3\'');
+  Protocol.Runtime.evaluate({expression: 'let b = 3'});
+  await dumpGlobalScopeVariables();
+
+  InspectorTest.log('Running \'const c = 4\'');
+  Protocol.Runtime.evaluate({expression: 'const c = 4'});
+  await dumpGlobalScopeVariables();
+
+  InspectorTest.log('Running \'var d = 5\'');
+  InspectorTest.log('(should not be in list of scoped variables)');
+  Protocol.Runtime.evaluate({expression: 'var d = 5'});
+  await dumpGlobalScopeVariables();
+
+  InspectorTest.log('Running \'class Foo{}\'');
+  Protocol.Runtime.evaluate({expression: 'class Foo{}'});
+  await dumpGlobalScopeVariables();
+
+  InspectorTest.log('Adding script with scope variables');
+  contextGroup.addScript(`
+  let e = 1;
+  const f = 2;
+  const g = 3;
+  class Boo {};
+  `);
+  await dumpGlobalScopeVariables();
+  InspectorTest.completeTest();
+})();
+
+async function dumpGlobalScopeVariables() {
+  let {result:{names}} =
+      await Protocol.Runtime.globalLexicalScopeNames();
+  InspectorTest.log('Values:');
+  for (let name of names) {
+    let {result:{result}} = await Protocol.Runtime.evaluate({expression: name});
+    if (result.value) {
+      InspectorTest.log(`${name} = ${result.value}`);
+    } else {
+      InspectorTest.log(`${name} =`);
+      InspectorTest.logMessage(result);
+    }
+  }
+  InspectorTest.log('');
+}

deps/v8/test/inspector/runtime/runtime-restore.js

@@ -1,6 +1,6 @@
 // Copyright 2017 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.v8
+// found in the LICENSE file.
 
 let {session, contextGroup, Protocol} = InspectorTest.start('Checks that Runtime agent correctly restore its state.');