Reland of Improve linearized pdf load/show time.

pdf/pdfium/pdfium_engine.h

Index: pdf/pdfium/pdfium_engine.h
diff --git a/pdf/pdfium/pdfium_engine.h b/pdf/pdfium/pdfium_engine.h
index 8f8609ad623b15b5cf702b85338b87ce16ca402c..0334a602433e801f199023f35b8f4e31e03e6837 100644
--- a/pdf/pdfium/pdfium_engine.h
+++ b/pdf/pdfium/pdfium_engine.h
@@ -108,16 +108,16 @@ class PDFiumEngine : public PDFEngine,
 #if defined(PDF_ENABLE_XFA)
   void SetScrollPosition(const pp::Point& position) override;
 #endif
-  bool IsProgressiveLoad() override;
   std::string GetMetadata(const std::string& key) override;
 
   // DocumentLoader::Client implementation.
   pp::Instance* GetPluginInstance() override;
-  pp::URLLoader CreateURLLoader() override;
-  void OnPartialDocumentLoaded() override;
+  std::unique_ptr<URLLoaderWrapper> CreateURLLoader() override;
   void OnPendingRequestComplete() override;
   void OnNewDataAvailable() override;
   void OnDocumentComplete() override;
+  void OnDocumentCanceled() override;
+  void CancelBrowserDownload() override;
 
   void UnsupportedFeature(int type);
   void FontSubstituted();
@@ -191,11 +191,11 @@ class PDFiumEngine : public PDFEngine,
   friend class SelectionChangeInvalidator;
 
   struct FileAvail : public FX_FILEAVAIL {
-    DocumentLoader* loader;
+    PDFiumEngine* engine;
   };
 
   struct DownloadHints : public FX_DOWNLOADHINTS {
-    DocumentLoader* loader;
+    PDFiumEngine* engine;
   };
 
   // PDFium interface to get block of data.
@@ -602,7 +602,7 @@ class PDFiumEngine : public PDFEngine,
   double current_zoom_;
   unsigned int current_rotation_;
 
-  DocumentLoader doc_loader_;  // Main document's loader.
+  std::unique_ptr<DocumentLoader> doc_loader_;  // Main document's loader.
   std::string url_;
   std::string headers_;
   pp::CompletionCallbackFactory<PDFiumEngine> find_factory_;
@@ -731,6 +731,11 @@ class PDFiumEngine : public PDFEngine,
   // to false after the user finishes getting their password.
   bool getting_password_;
 
+  // While true, the document try to be opened and parsed after download each
+  // part. Else the document will be opened and parsed only on finish of
+  // downloading.
+  bool process_when_pending_request_complete_ = true;
+
   DISALLOW_COPY_AND_ASSIGN(PDFiumEngine);
 };