Change PDFiumDocument::LoadDocument() to take a std::string.

already known. Change to const char* right before interacting with the
PDFium C API.

std: :string is slightly better than const char* since its length is
Change-Id: I429f6c05a5b517e73622909b7ac5583b27af6ea3
Reviewed-on: https://chromium-review.googlesource.com/c/1407923
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622611}

pdf/pdfium/pdfium_document.cc

@@ -94,13 +94,15 @@ void PDFiumDocument::ResetFPDFAvailability() {
   fpdf_availability_.reset();
 }
 
-void PDFiumDocument::LoadDocument(const char* password) {
+void PDFiumDocument::LoadDocument(const std::string& password) {
+  const char* password_cstr = password.empty() ? nullptr : password.c_str();
   if (doc_loader_->IsDocumentComplete() &&
       !FPDFAvail_IsLinearized(fpdf_availability_.get())) {
-    doc_handle_.reset(FPDF_LoadCustomDocument(file_access_.get(), password));
+    doc_handle_.reset(
+        FPDF_LoadCustomDocument(file_access_.get(), password_cstr));
   } else {
     doc_handle_.reset(
-        FPDFAvail_GetDocument(fpdf_availability_.get(), password));
+        FPDFAvail_GetDocument(fpdf_availability_.get(), password_cstr));
   }
 }
 

pdf/pdfium/pdfium_document.h

@@ -5,6 +5,9 @@
 #ifndef PDF_PDFIUM_PDFIUM_DOCUMENT_H_
 #define PDF_PDFIUM_PDFIUM_DOCUMENT_H_
 
+#include <memory>
+#include <string>
+
 #include "base/macros.h"
 #include "third_party/pdfium/public/cpp/fpdf_scopers.h"
 #include "third_party/pdfium/public/fpdf_dataavail.h"
@@ -32,7 +35,7 @@ class PDFiumDocument {
   void CreateFPDFAvailability();
   void ResetFPDFAvailability();
 
-  void LoadDocument(const char* password);
+  void LoadDocument(const std::string& password);
 
   void SetFormStatus();
   void InitializeForm(FPDF_FORMFILLINFO* form_info);

pdf/pdfium/pdfium_engine.cc

@@ -2645,12 +2645,9 @@ bool PDFiumEngine::TryLoadingDoc(const std::string& password,
     return true;
   }
 
-  const char* password_cstr = nullptr;
-  if (!password.empty()) {
-    password_cstr = password.c_str();
+  if (!password.empty())
     password_tries_remaining_--;
-  }
-  document_->LoadDocument(password_cstr);
+  document_->LoadDocument(password);
   if (!doc()) {
     if (FPDF_GetLastError() == FPDF_ERR_PASSWORD)
       *needs_password = true;