Clean up singleton implementation

core/fpdfapi/cpdf_modulemgr.cpp

Index: core/fpdfapi/cpdf_modulemgr.cpp
diff --git a/core/fpdfapi/cpdf_modulemgr.cpp b/core/fpdfapi/cpdf_modulemgr.cpp
index fe5368d3f7ca82ce8605324f5ed0107969224f24..454ffcd465ca1c1a139c0dcba8d505ce4d28efa3 100644
--- a/core/fpdfapi/cpdf_modulemgr.cpp
+++ b/core/fpdfapi/cpdf_modulemgr.cpp
@@ -11,25 +11,21 @@
 
 namespace {
 
-CPDF_ModuleMgr* g_FPDFAPI_pDefaultMgr = nullptr;
+CPDF_ModuleMgr* g_pDefaultMgr = nullptr;
 
 }  // namespace
 
 // static
 CPDF_ModuleMgr* CPDF_ModuleMgr::Get() {
-  return g_FPDFAPI_pDefaultMgr;
-}
-
-// static
-void CPDF_ModuleMgr::Create() {
-  ASSERT(!g_FPDFAPI_pDefaultMgr);
-  g_FPDFAPI_pDefaultMgr = new CPDF_ModuleMgr;
+  if (!g_pDefaultMgr)
+    g_pDefaultMgr = new CPDF_ModuleMgr;
+  return g_pDefaultMgr;
 }
 
 // static
 void CPDF_ModuleMgr::Destroy() {
-  delete g_FPDFAPI_pDefaultMgr;
-  g_FPDFAPI_pDefaultMgr = nullptr;
+  delete g_pDefaultMgr;
+  g_pDefaultMgr = nullptr;
 }
 
 CPDF_ModuleMgr::CPDF_ModuleMgr() : m_pCodecModule(nullptr) {}