Avoid cross-origin iframe issues when loading PDF in print preview

content/public/browser/url_data_source.cc

Index: content/public/browser/url_data_source.cc
diff --git a/content/public/browser/url_data_source.cc b/content/public/browser/url_data_source.cc
index 0c76c50afd0f41af02359306f6b042c96ceb2831..ce060966eca4f7b470907332ffcffcc442ef930b 100644
--- a/content/public/browser/url_data_source.cc
+++ b/content/public/browser/url_data_source.cc
@@ -61,4 +61,12 @@ std::string URLDataSource::GetAccessControlAllowOriginForOrigin(
   return std::string();
 }
 
+void URLDataSource::WillServiceRequest(
+      const net::URLRequest* request,
+      std::string* path) const {
+  // In the normal case we want to remove any query strings from the path. This
+  // may not be true for subclasses which can override this behavior.
+  *path = path->substr(0, path->find_last_of('?'));

[Charlie Reis, 2015/07/20 16:49:09]

I don't think this is a good change to make.  Things in content/public should
mainly be interfaces, and the other implementations in this file are small and
don't have side effects.  This code makes a meaningful change to the path in a
way that isn't obvious, and it's easy to accidentally prevent this change
(without realizing it) by overriding the method.

+}
+
 }  // namespace content