Remove m_pDownloadCallback.

Not only unused, but ugly-looking.
Fix lint along the way.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1709313002 .
diff --git a/core/include/fpdfapi/fpdf_module.h b/core/include/fpdfapi/fpdf_module.h
index 4856184..dffef96 100644
--- a/core/include/fpdfapi/fpdf_module.h
+++ b/core/include/fpdfapi/fpdf_module.h
@@ -78,7 +78,6 @@
   CCodec_ModuleMgr* m_pCodecModule;
   std::unique_ptr<IPDF_RenderModule> m_pRenderModule;
   std::unique_ptr<IPDF_PageModule> m_pPageModule;
-  FX_BOOL (*m_pDownloadCallback)(const FX_CHAR* module_name);
   CFX_PrivateData m_privateData;
 };
 
@@ -87,8 +86,8 @@
   virtual ~IPDF_PageModule() {}
 
   virtual CPDF_DocPageData* CreateDocData(CPDF_Document* pDoc) = 0;
-  virtual void ReleaseDoc(CPDF_Document*) = 0;
-  virtual void ClearDoc(CPDF_Document*) = 0;
+  virtual void ReleaseDoc(CPDF_Document* pDoc) = 0;
+  virtual void ClearDoc(CPDF_Document* pDoc) = 0;
   virtual CPDF_FontGlobals* GetFontGlobals() = 0;
   virtual void ClearStockFont(CPDF_Document* pDoc) = 0;
   virtual void NotifyCJKAvailable() = 0;
@@ -100,11 +99,11 @@
   virtual ~IPDF_RenderModule() {}
 
   virtual CPDF_DocRenderData* CreateDocData(CPDF_Document* pDoc) = 0;
-  virtual void DestroyDocData(CPDF_DocRenderData*) = 0;
-  virtual void ClearDocData(CPDF_DocRenderData*) = 0;
+  virtual void DestroyDocData(CPDF_DocRenderData* pDocRenderData) = 0;
+  virtual void ClearDocData(CPDF_DocRenderData* pDocRenderData) = 0;
   virtual CPDF_DocRenderData* GetRenderData() = 0;
   virtual CPDF_PageRenderCache* CreatePageCache(CPDF_Page* pPage) = 0;
-  virtual void DestroyPageCache(CPDF_PageRenderCache*) = 0;
+  virtual void DestroyPageCache(CPDF_PageRenderCache* pCache) = 0;
 };
 
 #endif  // CORE_INCLUDE_FPDFAPI_FPDF_MODULE_H_