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

content/browser/webui/web_ui_data_source_impl.cc

Index: content/browser/webui/web_ui_data_source_impl.cc
diff --git a/content/browser/webui/web_ui_data_source_impl.cc b/content/browser/webui/web_ui_data_source_impl.cc
index 06a4c8994d43abeb4c71bae7053398cf2f27c936..9c9373197cf23b9696b8e5bf944651ae3a9210bc 100644
--- a/content/browser/webui/web_ui_data_source_impl.cc
+++ b/content/browser/webui/web_ui_data_source_impl.cc
@@ -74,6 +74,11 @@ class WebUIDataSourceImpl::InternalDataSource : public URLDataSource {
   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_;