Defer deletion in PrintWebViewHelper while handling IPC messages.

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 652fbf03d63d0459138f1723bf2c72fc6113b790..15d2c288e78a4722d272ce1b784339b82fdad075 100644
--- a/components/printing/renderer/print_web_view_helper.h
+++ b/components/printing/renderer/print_web_view_helper.h
@@ -449,7 +449,7 @@ class PrintWebViewHelper
     // Helper functions
     int GetNextPageNumber();
     bool IsRendering() const;
-    bool IsModifiable();
+    bool IsModifiable() const;
     bool HasSelection();
     bool IsLastPageOfPrintReadyMetafile() const;
     bool IsFinalPageRendered() const;
@@ -487,6 +487,8 @@ class PrintWebViewHelper
     // Reset some of the internal rendering context.
     void ClearContext();
 
+    void CalculateIsModifiable();
+
     // Specifies what to render for print preview.
     FrameReference source_frame_;
     blink::WebNode source_node_;
@@ -506,6 +508,9 @@ class PrintWebViewHelper
     // True, when draft pages needs to be generated.
     bool generate_draft_pages_;
 
+    // True, if the document source is modifiable. e.g. HTML and not PDF.
+    bool is_modifiable_;

[lfg, 2017/04/27 19:44:14]

This seems to be uninitialized in the constructor.

[Lei Zhang, 2017/04/27 20:31:24]

Right. It's not ever used until after one of the Init* methods get called. I'll
initialize since it's generally a good thing to do. I also added a DCHECK to
make sure we are not trying to access it when |state_| is UNINITIALIZED.

+
     // Specifies the total number of pages in the print ready metafile.
     int print_ready_metafile_page_count_;
 
@@ -515,6 +520,8 @@ class PrintWebViewHelper
     enum PrintPreviewErrorBuckets error_;
 
     State state_;
+
+    DISALLOW_COPY_AND_ASSIGN(PrintPreviewContext);
   };
 
   class ScriptingThrottler {
@@ -541,6 +548,7 @@ class PrintWebViewHelper
   bool is_loading_;
   bool is_scripted_preview_delayed_;
   int ipc_nesting_level_;
+  bool render_frame_gone_;
 
   // Used to fix a race condition where the source is a PDF and print preview
   // hangs because RequestPrintPreview is called before DidStopLoading() is