Allow the PDF extension for chrome://print pages.

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 a5364fbf2b2810e36be883d8a3bb4c7fc156ca31..2d6d24a916d5f43ec1a34d25881678357dd0c934 100644
--- a/content/browser/webui/web_ui_data_source_impl.cc
+++ b/content/browser/webui/web_ui_data_source_impl.cc
@@ -61,6 +61,11 @@ class WebUIDataSourceImpl::InternalDataSource : public URLDataSource {
   bool ShouldAddContentSecurityPolicy() const override {
     return parent_->add_csp_;
   }
+  std::string GetContentSecurityPolicyScriptSrc() const override {
+    if (parent_->script_src_set_)
+      return parent_->script_src_;
+    return URLDataSource::GetContentSecurityPolicyScriptSrc();
+  }
   std::string GetContentSecurityPolicyObjectSrc() const override {
     if (parent_->object_src_set_)
       return parent_->object_src_;
@@ -88,6 +93,7 @@ WebUIDataSourceImpl::WebUIDataSourceImpl(const std::string& source_name)
       source_name_(source_name),
       default_resource_(-1),
       add_csp_(true),
+      script_src_set_(false),
       object_src_set_(false),
       frame_src_set_(false),
       deny_xframe_options_(true),
@@ -180,6 +186,12 @@ void WebUIDataSourceImpl::DisableContentSecurityPolicy() {
   add_csp_ = false;
 }
 
+void WebUIDataSourceImpl::OverrideContentSecurityPolicyScriptSrc(
+    const std::string& data) {
+  script_src_set_ = true;
+  script_src_ = data;
+}
+
 void WebUIDataSourceImpl::OverrideContentSecurityPolicyObjectSrc(
     const std::string& data) {
   object_src_set_ = true;