Add chrome.webstore API methods to allow sites to see progress of installation

chrome/renderer/extensions/webstore_bindings.h

Index: chrome/renderer/extensions/webstore_bindings.h
diff --git a/chrome/renderer/extensions/webstore_bindings.h b/chrome/renderer/extensions/webstore_bindings.h
index b729150a9855753754dfb6c0c20657292c2e48de..5df521a455bd8a7857752be46da423d7086f76bb 100644
--- a/chrome/renderer/extensions/webstore_bindings.h
+++ b/chrome/renderer/extensions/webstore_bindings.h
@@ -30,6 +30,10 @@ class WebstoreBindings : public ChromeV8Extension,
   void OnInlineWebstoreInstallResponse(
       int install_id, bool success, const std::string& error);
 
+  void OnInlineInstallStageChanged(int stage);
+
+  void OnInlineInstallDownloadProgress(int percent_downloaded);
+
   // Extracts a Web Store item ID from a <link rel="chrome-webstore-item"
   // href="https://chrome.google.com/webstore/detail/id"> node found in the
   // frame. On success, true will be returned and the |webstore_item_id|