Check for PrintWebViewHelper validity when running nested message loops.

components/printing/renderer/print_web_view_helper.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_PRINTING_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 #define COMPONENTS_PRINTING_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 54 matching lines @@
   ~FrameReference();
 
   void Reset(blink::WebLocalFrame* frame);
 
   blink::WebLocalFrame* GetFrame();
   blink::WebView* view();
 
  private:
   blink::WebView* view_;
   blink::WebLocalFrame* frame_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameReference);
 };
 
 // PrintWebViewHelper handles most of the printing grunt work for RenderView.
 // We plan on making print asynchronous and that will require copying the DOM
 // of the document and creating a new WebView with the contents.
 class PrintWebViewHelper
     : public content::RenderFrameObserver,
       public content::RenderFrameObserverTracker<PrintWebViewHelper> {
  public:
   class Delegate {
@@ skipping 130 matching lines @@
   // Finalize the print ready preview document.
   bool FinalizePrintReadyDocument();
 #endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)
 
   // Enable/Disable printing.
   void OnSetPrintingEnabled(bool enabled);
 
   // Main printing code -------------------------------------------------------
 
 #if BUILDFLAG(ENABLE_BASIC_PRINTING)
-  // |is_scripted| should be true when the call is coming from window.print()
+  // Print with the system dialog.
+  // |is_scripted| should be true when the call is coming from window.print().
+  // WARNING: |this| may be gone after this method returns.
   void Print(blink::WebLocalFrame* frame,
              const blink::WebNode& node,
              bool is_scripted);
 #endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)
 
   // Notification when printing is done - signal tear-down/free resources.
   void DidFinishPrinting(PrintingResult result);
 
   // Print Settings -----------------------------------------------------------
 
@@ skipping 12 matching lines @@
       PrintHostMsg_SetOptionsFromDocument_Params* options);
 
   // Update the current print settings with new |passed_job_settings|.
   // |passed_job_settings| dictionary contains print job details such as printer
   // name, number of copies, page range, etc.
   bool UpdatePrintSettings(blink::WebLocalFrame* frame,
                            const blink::WebNode& node,
                            const base::DictionaryValue& passed_job_settings);
 #endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)
 
+#if BUILDFLAG(ENABLE_BASIC_PRINTING)
   // Get final print settings from the user.
-  // Return false if the user cancels or on error.
-  bool GetPrintSettingsFromUser(blink::WebLocalFrame* frame,
-                                const blink::WebNode& node,
-                                int expected_pages_count,
-                                bool is_scripted);
+  // WARNING: |this| may be gone after this method returns.
+  void GetPrintSettingsFromUser(
+      blink::WebLocalFrame* frame,
+      const blink::WebNode& node,
+      int expected_pages_count,
+      bool is_scripted,
+      PrintMsg_PrintPages_Params* print_settings);
+#endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)
 
   // Page Printing / Rendering ------------------------------------------------
-
 #if BUILDFLAG(ENABLE_BASIC_PRINTING)
   void OnFramePreparedForPrintPages();
   void PrintPages();
   bool PrintPagesNative(blink::WebLocalFrame* frame, int page_count);
   void FinishFramePrinting();
   // Render the frame for printing.
   bool RenderPagesForPrint(blink::WebLocalFrame* frame,
                            const blink::WebNode& node);
 #endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)
 
@@ skipping 68 matching lines @@
   // Return true if script initiated printing is currently
   // allowed. |user_initiated| should be true when a user event triggered the
   // script, most likely by pressing a print button on the page.
   bool IsScriptInitiatedPrintAllowed(blink::WebFrame* frame,
                                      bool user_initiated);
 
 #if BUILDFLAG(ENABLE_PRINT_PREVIEW)
   // Shows scripted print preview when options from plugin are available.
   void ShowScriptedPrintPreview();
 
+  // WARNING: |this| may be gone after this method returns when |type| is
+  // PRINT_PREVIEW_SCRIPTED.
   void RequestPrintPreview(PrintPreviewRequestType type);
 
   // Checks whether print preview should continue or not.
   // Returns true if canceling, false if continuing.
   bool CheckForCancel();
 
   // Notifies the browser a print preview page has been rendered.
   // |page_number| is 0-based.
   // For a valid |page_number| with modifiable content,
   // |metafile| is the rendered page. Otherwise |metafile| is NULL.
@@ skipping 163 matching lines @@
   base::Closure on_stop_loading_closure_;
 
   base::WeakPtrFactory<PrintWebViewHelper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintWebViewHelper);
 };
 
 }  // namespace printing
 
 #endif  // COMPONENTS_PRINTING_RENDERER_PRINT_WEB_VIEW_HELPER_H_