Bug 1162329 - Fix the autocomplete popup opening with cached results. r=felipe

The e10s autocomplete popup doesn't pop back up if
nsAutoCompleteController.cpp decides to reuse its cached autocomplete result.
We need to detect when this happens and open the popup in the parent.

toolkit/components/satchel/AutoCompleteE10S.jsm

@@ -82,10 +82,13 @@ this.AutoCompleteE10S = {
                          getService(Ci.nsIMessageListenerManager);
     messageManager.addMessageListener("FormAutoComplete:SelectBy", this);
     messageManager.addMessageListener("FormAutoComplete:GetSelectedIndex", this);
+    messageManager.addMessageListener("FormAutoComplete:MaybeOpenPopup", this);
     messageManager.addMessageListener("FormAutoComplete:ClosePopup", this);
   },
 
   _initPopup: function(browserWindow, rect, direction) {
+    this._popupCache = { browserWindow, rect, direction };
+
     this.browser = browserWindow.gBrowser.selectedBrowser;
     this.popup = this.browser.autoCompletePopup;
     this.popup.hidden = false;
@@ -122,6 +125,7 @@ this.AutoCompleteE10S = {
       this.popup.closePopup();
     }
 
+    this._resultCache = results;
     return resultsArray;
   },
 
@@ -192,6 +196,19 @@ this.AutoCompleteE10S = {
       case "FormAutoComplete:GetSelectedIndex":
         return this.popup.selectedIndex;
 
+      case "FormAutoComplete:MaybeOpenPopup":
+        if (AutoCompleteE10SView.treeData.length > 0 &&
+            !this.popup.popupOpen) {
+          // This happens when one of the arrow keys is pressed after a search
+          // has already been completed. nsAutoCompleteController tries to
+          // re-use its own cache of the results without re-doing the search.
+          // Detect that and show the popup here.
+          this.showPopupWithResults(this._popupCache.browserWindow,
+                                    this._popupCache.rect,
+                                    this._resultCache);
+        }
+        break;
+
       case "FormAutoComplete:ClosePopup":
         this.popup.closePopup();
         break;
@@ -202,7 +219,7 @@ this.AutoCompleteE10S = {
     this.browser.messageManager.sendAsyncMessage(
       "FormAutoComplete:HandleEnter",
       { selectedIndex: this.popup.selectedIndex,
-        IsPopupSelection: aIsPopupSelection }
+        isPopupSelection: aIsPopupSelection }
     );
   },
 

toolkit/content/browser-child.js

@@ -551,6 +551,12 @@ let AutoCompletePopup = {
   },
 
   openAutocompletePopup: function (input, element) {
+    if (!this._popupOpen) {
+      // The search itself normally opens the popup itself, but in some cases,
+      // nsAutoCompleteController tries to use cached results so notify our
+      // popup to reuse the last results.
+      sendAsyncMessage("FormAutoComplete:MaybeOpenPopup", {});
+    }
     this._input = input;
     this._popupOpen = true;
   },