Use string pools in some dictionaries

core/fpdfdoc/cpdf_formfield_unittest.cpp

Index: core/fpdfdoc/cpdf_formfield_unittest.cpp
diff --git a/core/fpdfdoc/cpdf_formfield_unittest.cpp b/core/fpdfdoc/cpdf_formfield_unittest.cpp
index 7677f452847f4253c342ac34bc2fa3ca5cddfe95..35fa24e21fb7f16d8d7f177c9831f08a81013833 100644
--- a/core/fpdfdoc/cpdf_formfield_unittest.cpp
+++ b/core/fpdfdoc/cpdf_formfield_unittest.cpp
@@ -12,26 +12,26 @@ TEST(cpdf_formfield, FPDF_GetFullName) {
   EXPECT_TRUE(name.IsEmpty());
 
   CPDF_IndirectObjectHolder obj_holder;
-  CPDF_Dictionary* root = new CPDF_Dictionary;
+  CPDF_Dictionary* root = new CPDF_Dictionary(nullptr);
   obj_holder.AddIndirectObject(root);
   root->SetNameFor("T", "foo");
   name = FPDF_GetFullName(root);
   EXPECT_STREQ("foo", name.UTF8Encode().c_str());
 
-  CPDF_Dictionary* dict1 = new CPDF_Dictionary;
+  CPDF_Dictionary* dict1 = new CPDF_Dictionary(nullptr);
   obj_holder.AddIndirectObject(dict1);
   dict1->SetNameFor("T", "bar");
   root->SetReferenceFor("Parent", &obj_holder, dict1);
   name = FPDF_GetFullName(root);
   EXPECT_STREQ("bar.foo", name.UTF8Encode().c_str());
 
-  CPDF_Dictionary* dict2 = new CPDF_Dictionary;
+  CPDF_Dictionary* dict2 = new CPDF_Dictionary(nullptr);
   obj_holder.AddIndirectObject(dict2);
   dict1->SetFor("Parent", dict2);
   name = FPDF_GetFullName(root);
   EXPECT_STREQ("bar.foo", name.UTF8Encode().c_str());
 
-  CPDF_Dictionary* dict3 = new CPDF_Dictionary;
+  CPDF_Dictionary* dict3 = new CPDF_Dictionary(nullptr);
   obj_holder.AddIndirectObject(dict3);
   dict3->SetNameFor("T", "qux");
   dict2->SetReferenceFor("Parent", &obj_holder, dict3);