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

content/browser/webui/web_ui_data_source_impl.cc

 // 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.
 
 #include "content/browser/webui/web_ui_data_source_impl.h"
 
 #include <stddef.h>
 
 #include <string>
 
@@ skipping 56 matching lines @@
     return URLDataSource::GetContentSecurityPolicyObjectSrc();
   }
   std::string GetContentSecurityPolicyFrameSrc() const override {
     if (parent_->frame_src_set_)
       return parent_->frame_src_;
     return URLDataSource::GetContentSecurityPolicyFrameSrc();
   }
   bool ShouldDenyXFrameOptions() const override {
     return parent_->deny_xframe_options_;
   }
+  void WillServiceRequest(const net::URLRequest* request,
+                          std::string* path) const override {
+    // We want to remove any query strings from the path.

[Primiano Tucci (use gerrit), 2016/01/04 18:50:38]

The funny thing is that [1] relies on the opposite behavior.
(And sadly there doesn't seem to be any test convering the tracing UI
integration :/)

[1]
https://code.google.com/p/chromium/codesearch#chromium/src/content/browser/tr...

+    *path = path->substr(0, path->find_first_of('?'));
+  }
 
  private:
   WebUIDataSourceImpl* parent_;
 };
 
 WebUIDataSourceImpl::WebUIDataSourceImpl(const std::string& source_name)
     : URLDataSourceImpl(
           source_name,
           new InternalDataSource(this)),
       source_name_(source_name),
@@ skipping 154 matching lines @@
 }
 
 void WebUIDataSourceImpl::SendFromResourceBundle(
     const URLDataSource::GotDataCallback& callback, int idr) {
   scoped_refptr<base::RefCountedStaticMemory> response(
       GetContentClient()->GetDataResourceBytes(idr));
   callback.Run(response.get());
 }
 
 }  // namespace content