Check for PrintWebViewHelper validity when running nested message loops.

components/printing/renderer/print_web_view_helper.h

Index: components/printing/renderer/print_web_view_helper.h
diff --git a/components/printing/renderer/print_web_view_helper.h b/components/printing/renderer/print_web_view_helper.h
index 2dad908dc266d66ddaba8f4a0736e934d3d0ec4f..d07f864c397368d912b4c29d4124385704cf6514 100644
--- a/components/printing/renderer/print_web_view_helper.h
+++ b/components/printing/renderer/print_web_view_helper.h
@@ -42,6 +42,7 @@ struct PrintHostMsg_SetOptionsFromDocument_Params;
 
 namespace base {
 class DictionaryValue;
+class ScopedClosureRunner;
 }
 
 namespace blink {
@@ -72,6 +73,8 @@ class FrameReference {
  private:
   blink::WebView* view_;
   blink::WebLocalFrame* frame_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameReference);
 };
 
 // PrintWebViewHelper handles most of the printing grunt work for RenderView.
@@ -81,6 +84,9 @@ class PrintWebViewHelper
     : public content::RenderFrameObserver,
       public content::RenderFrameObserverTracker<PrintWebViewHelper> {
  public:
+  using GetPrintSettingsFromUserCallback = base::Callback<void(
+      const PrintMsg_PrintPages_Params& /* print_settings */)>;
+
   class Delegate {
    public:
     virtual ~Delegate() {}
@@ -222,10 +228,20 @@ class PrintWebViewHelper
   // Main printing code -------------------------------------------------------
 
 #if BUILDFLAG(ENABLE_BASIC_PRINTING)
-  // |is_scripted| should be true when the call is coming from window.print()
-  void Print(blink::WebLocalFrame* frame,
-             const blink::WebNode& node,
-             bool is_scripted);
+  // Start printing with the system dialog. Continues to FinishPrint() below
+  // eventually.
+  // |is_scripted| should be true when the call is coming from window.print().
+  // WARNING: |this| may be gone after this method returns.
+  void StartPrint(blink::WebLocalFrame* frame,
+                  const blink::WebNode& node,
+                  bool is_scripted,
+                  bool reset_print_node_in_progress);
+
+  // Do the second phase of printing, since showing the system dialog in the
+  // middle may require callbacks. Use the saved parameters and do the
+  // rendering.
+  void FinishPrint(std::unique_ptr<FrameReference> frame_ref,
+                   const blink::WebNode& node);
 #endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)
 
   // Notification when printing is done - signal tear-down/free resources.
@@ -255,15 +271,27 @@ class PrintWebViewHelper
                            const base::DictionaryValue& passed_job_settings);
 #endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)
 
-  // 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);
+#if BUILDFLAG(ENABLE_BASIC_PRINTING)
+  // Get final print settings from the user and eventually call
+  // OnGetPrintSettingsFromUser().
+  // WARNING: |this| may be gone after this method returns.
+  void GetPrintSettingsFromUser(
+      std::unique_ptr<FrameReference> frame_ref,
+      const blink::WebNode& node,
+      int expected_pages_count,
+      bool is_scripted,
+      std::unique_ptr<base::ScopedClosureRunner> on_finish_calback);
+
+  // Do the actual printing rendering after Print() gets settings from the
+  // system dialog.
+  void OnGetPrintSettingsFromUser(
+      std::unique_ptr<FrameReference> frame_ref,
+      const blink::WebNode& node,
+      std::unique_ptr<base::ScopedClosureRunner> on_finish_calback,
+      const PrintMsg_PrintPages_Params& print_settings);
+#endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)
 
   // Page Printing / Rendering ------------------------------------------------
-
 #if BUILDFLAG(ENABLE_BASIC_PRINTING)
   void OnFramePreparedForPrintPages();
   void PrintPages();
@@ -352,6 +380,8 @@ class PrintWebViewHelper
   // 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.
@@ -366,6 +396,12 @@ class PrintWebViewHelper
   bool PreviewPageRendered(int page_number, PdfMetafileSkia* metafile);
 #endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)
 
+  void reset_scripted_preview_delayed() {
+    is_scripted_preview_delayed_ = false;
+  }
+
+  void print_node_in_progress_finished() { print_node_in_progress_ = false; }
+
   void SetPrintPagesParams(const PrintMsg_PrintPages_Params& settings);
 
   // WebView used only to print the selection.