Don't call WebContents::DownloadImage() callback if the WebContents were deleted

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index 81bdf75e572f85f2d3139fa35549f00103d31ad1..29f7c074a425ab04c7b5be84bea61159b34712b9 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -818,6 +818,12 @@ class CONTENT_EXPORT WebContentsImpl
   // all the unique RenderWidgetHostViews.
   std::set<RenderWidgetHostView*> GetRenderWidgetHostViewsInTree();
 
+  // Called with the result of a DownloadImage() request.
+  void OnDidDownloadImage(const ImageDownloadCallback& callback,
+                          int id,
+                          const GURL& image_url,
+                          image_downloader::DownloadResultPtr result);
+
   // Callback function when showing JavaScript dialogs.  Takes in a routing ID
   // pair to identify the RenderFrameHost that opened the dialog, because it's
   // possible for the RenderFrameHost to be deleted by the time this is called.
@@ -1307,6 +1313,7 @@ class CONTENT_EXPORT WebContentsImpl
 
   bool page_scale_factor_is_one_;
 
+  base::WeakPtrFactory<WebContentsImpl> download_image_weak_factory_;

[jam, 2016/02/12 23:31:42]

since this is never reset, just make this be weak_factory_ so that if other code
needs it they can use it.

   base::WeakPtrFactory<WebContentsImpl> loading_weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsImpl);