Hide heap methods where possible.

test/cctest/test-heap.cc

Index: test/cctest/test-heap.cc
diff --git a/test/cctest/test-heap.cc b/test/cctest/test-heap.cc
index c9e5d50add4e63269f675adcb7acfe404754b5b4..dfc1ab5c4f7ee3b162607e4ea6dd48134b28a367 100644
--- a/test/cctest/test-heap.cc
+++ b/test/cctest/test-heap.cc
@@ -595,13 +595,20 @@ static const char* not_so_random_string_table[] = {
 
 
 static void CheckInternalizedStrings(const char** strings) {
-  Factory* factory = CcTest::i_isolate()->factory();
+  Isolate* isolate = CcTest::i_isolate();
+  Factory* factory = isolate->factory();
   for (const char* string = *strings; *strings != 0; string = *strings++) {
-    Handle<String> a = factory->InternalizeUtf8String(string);
+    HandleScope scope(isolate);
+    Handle<String> a =
+        isolate->factory()->InternalizeUtf8String(CStrVector(string));
+    // InternalizeUtf8String may return a failure if a GC is needed.
     CHECK(a->IsInternalizedString());
     Handle<String> b = factory->InternalizeUtf8String(string);
     CHECK_EQ(*b, *a);
-    CHECK(String::cast(*b)->IsUtf8EqualTo(CStrVector(string)));
+    CHECK(b->IsUtf8EqualTo(CStrVector(string)));
+    b = isolate->factory()->InternalizeUtf8String(CStrVector(string));
+    CHECK_EQ(*b, *a);
+    CHECK(b->IsUtf8EqualTo(CStrVector(string)));
   }
 }
 
@@ -977,7 +984,7 @@ TEST(Regression39128) {
   // Test case for crbug.com/39128.
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
-  Heap* heap = isolate->heap();
+  TestHeap* heap = CcTest::test_heap();
 
   // Increase the chance of 'bump-the-pointer' allocation in old space.
   heap->CollectAllGarbage(Heap::kAbortIncrementalMarkingMask);