Revert 111252 - Switch MHTMLGenerationManager to use a Callback.

chrome/browser/extensions/extension_save_page_api.cc

Index: chrome/browser/extensions/extension_save_page_api.cc
===================================================================
--- chrome/browser/extensions/extension_save_page_api.cc	(revision 111255)
+++ chrome/browser/extensions/extension_save_page_api.cc	(working copy)
@@ -4,7 +4,6 @@
 
 #include "chrome/browser/extensions/extension_save_page_api.h"
 
-#include "base/bind.h"
 #include "base/file_util.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_tab_util.h"
@@ -106,27 +105,46 @@
     return;
   }
 
-  MHTMLGenerationManager::GenerateMHTMLCallback callback =
-      base::Bind(&SavePageAsMHTMLFunction::MHTMLGenerated, this);
-
+  registrar_.Add(
+      this, content::NOTIFICATION_MHTML_GENERATED,
+      content::Source<RenderViewHost>(tab_contents->render_view_host()));
+  // TODO(jcivelli): we should listen for navigation in the tab, tab closed,
+  //                 renderer died.
   g_browser_process->mhtml_generation_manager()->GenerateMHTML(
-      tab_contents, mhtml_path_, callback);
+      tab_contents, mhtml_path_);
 }
 
-void SavePageAsMHTMLFunction::MHTMLGenerated(const FilePath& file_path,
-                                             int64 mhtml_file_size) {
-  DCHECK(mhtml_path_ == file_path);
-  if (mhtml_file_size <= 0) {
+void SavePageAsMHTMLFunction::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  DCHECK(type == content::NOTIFICATION_MHTML_GENERATED);
+
+  const MHTMLGenerationManager::NotificationDetails* save_details =
+      content::Details<MHTMLGenerationManager::NotificationDetails>(details).
+          ptr();
+
+  if (mhtml_path_ != save_details->file_path) {
+    // This could happen if there are concurrent MHTML generations going on for
+    // the same tab.
+    LOG(WARNING) << "Received a notification that MHTML was generated but for a"
+        " different file.";
+    return;
+  }
+
+  registrar_.RemoveAll();
+
+  if (save_details->file_size <= 0) {
     ReturnFailure(kMHTMLGenerationFailedError);
     return;
   }
 
-  if (mhtml_file_size > std::numeric_limits<int>::max()) {
+  if (save_details->file_size > std::numeric_limits<int>::max()) {
     ReturnFailure(kFileTooBigError);
     return;
   }
 
-  ReturnSuccess(mhtml_file_size);
+  ReturnSuccess(save_details->file_size);
 }
 
 void SavePageAsMHTMLFunction::ReturnFailure(const std::string& error) {