Get signals working in the EXTRA_DATA section of MHTML

content/browser/download/mhtml_generation_manager.h

Index: content/browser/download/mhtml_generation_manager.h
diff --git a/content/browser/download/mhtml_generation_manager.h b/content/browser/download/mhtml_generation_manager.h
index e30001535b03735758e09f2734d69ce5cd1c03d7..5803e3a9c3c11ae2226132d16406c9e82f292785 100644
--- a/content/browser/download/mhtml_generation_manager.h
+++ b/content/browser/download/mhtml_generation_manager.h
@@ -15,7 +15,9 @@
 #include "base/macros.h"
 #include "base/memory/singleton.h"
 #include "base/process/process.h"
+#include "base/supports_user_data.h"
 #include "content/common/download/mhtml_save_status.h"
+#include "content/public/browser/web_contents.h"
 #include "content/public/common/mhtml_generation_params.h"
 #include "ipc/ipc_platform_file.h"
 
@@ -34,7 +36,7 @@ class WebContents;
 // MHTMLGenerationManager is a singleton.  Each call to SaveMHTML method creates
 // a new instance of MHTMLGenerationManager::Job that tracks generation of a
 // single MHTML file.
-class MHTMLGenerationManager {
+class CONTENT_EXPORT MHTMLGenerationManager {
  public:
   static MHTMLGenerationManager* GetInstance();
 
@@ -58,6 +60,16 @@ class MHTMLGenerationManager {
       const std::set<std::string>& digests_of_uris_of_serialized_resources,
       base::TimeDelta renderer_main_thread_time);
 
+  // Add an extra MHTML part to the data structure stored by the WebContents.
+  // This will take care of generating the boundary line.  This will also set
+  // the content-type and content-location headers to the values provided, and
+  // use the body provided.
+  static void StashMHTMLPartForAdditionToPage(
+      content::WebContents* contents,
+      const std::string& content_type,
+      const std::string& content_location,
+      const std::string& body);
+
  private:
   friend struct base::DefaultSingletonTraits<MHTMLGenerationManager>;
   class Job;