Fix build of pdf_hint_table_fuzzer.

Restore CPDF_Dictionary default constructor.
Use it in places where reasonable in the code.

TBR=dsinclair@chromium.org
TBR=thestig@chromium.org

Review-Url: https://codereview.chromium.org/2383843002
diff --git a/fpdfsdk/fpdfdoc_unittest.cpp b/fpdfsdk/fpdfdoc_unittest.cpp
index e39b732..70d136b 100644
--- a/fpdfsdk/fpdfdoc_unittest.cpp
+++ b/fpdfsdk/fpdfdoc_unittest.cpp
@@ -64,7 +64,7 @@
     m_pDoc = WrapUnique(new CPDF_TestPdfDocument());
     m_pIndirectObjs = m_pDoc->GetHolder();
     // Setup the root directory.
-    m_pRootObj.reset(new CPDF_Dictionary(CFX_WeakPtr<CFX_ByteStringPool>()));
+    m_pRootObj.reset(new CPDF_Dictionary());
     m_pDoc->SetRoot(m_pRootObj.get());
   }
 
@@ -79,8 +79,7 @@
     std::vector<DictObjInfo> info;
     for (int i = 0; i < num; ++i) {
       // Objects created will be released by the document.
-      CPDF_Dictionary* obj(
-          new CPDF_Dictionary(CFX_WeakPtr<CFX_ByteStringPool>()));
+      CPDF_Dictionary* obj = new CPDF_Dictionary();
       info.push_back({m_pIndirectObjs->AddIndirectObject(obj), obj});
     }
     return info;
@@ -104,8 +103,7 @@
   }
   {
     // Empty bookmark tree.
-    m_pRootObj->SetFor("Outlines",
-                       new CPDF_Dictionary(CFX_WeakPtr<CFX_ByteStringPool>()));
+    m_pRootObj->SetFor("Outlines", new CPDF_Dictionary());
     std::unique_ptr<unsigned short, pdfium::FreeDeleter> title =
         GetFPDFWideString(L"");
     EXPECT_EQ(nullptr, FPDFBookmark_Find(m_pDoc.get(), title.get()));