Count external string resources that were assigned to symbol strings.

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 3be068009e275e53bb60903d812af6f841ab6069..70d1cde9caafd6823f67d6fb83df81a0a9825734 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -14816,11 +14816,13 @@ THREADED_TEST(GetHeapStatistics) {
 
 class VisitorImpl : public v8::ExternalResourceVisitor {
  public:
-  VisitorImpl(TestResource* r1, TestResource* r2)
+  VisitorImpl(TestResource* r1, TestResource* r2, TestResource* r3)
       : resource1_(r1),
         resource2_(r2),
+        resource3_(r3),
         found_resource1_(false),
-        found_resource2_(false) {}
+        found_resource2_(false),
+        found_resource3_(false) {}
   virtual ~VisitorImpl() {}
   virtual void VisitExternalString(v8::Handle<v8::String> string) {
     if (!string->IsExternal()) {
@@ -14838,17 +14840,24 @@ class VisitorImpl : public v8::ExternalResourceVisitor {
       CHECK(!found_resource2_);
       found_resource2_ = true;
     }
+    if (resource3_ == resource) {
+      CHECK(!found_resource3_);
+      found_resource3_ = true;
+    }
   }
   void CheckVisitedResources() {
     CHECK(found_resource1_);
     CHECK(found_resource2_);
+    CHECK(found_resource3_);
   }
 
  private:
   v8::String::ExternalStringResource* resource1_;
   v8::String::ExternalStringResource* resource2_;
+  v8::String::ExternalStringResource* resource3_;
   bool found_resource1_;
   bool found_resource2_;
+  bool found_resource3_;
 };
 
 TEST(VisitExternalStrings) {
@@ -14860,12 +14869,17 @@ TEST(VisitExternalStrings) {
   v8::Local<v8::String> string1 = v8::String::NewExternal(resource1);
   TestResource* resource2 = new TestResource(two_byte_string);
   v8::Local<v8::String> string2 = v8::String::NewExternal(resource2);
+  TestResource* resource3 = new TestResource(two_byte_string);
+  v8::Local<v8::String> symbol = v8::String::NewSymbol(string);
+  symbol->MakeExternal(resource3);
 
-  // We need to add usages for string1 and string2 to avoid warnings in GCC 4.7
+  // We need to add usages for string1, string2 and symbol string
+  // to avoid warnings in GCC 4.7
   CHECK(string1->IsExternal());
   CHECK(string2->IsExternal());
+  CHECK(symbol->IsExternal());
 
-  VisitorImpl visitor(resource1, resource2);
+  VisitorImpl visitor(resource1, resource2, resource3);
   v8::V8::VisitExternalResources(&visitor);
   visitor.CheckVisitedResources();
 }