Bug 1169723 - Load view source frame script lazily. r=mconley

browser/base/content/browser.js

@@ -986,7 +986,6 @@ var gBrowserInit = {
     mm.loadFrameScript("chrome://browser/content/content.js", true);
     mm.loadFrameScript("chrome://browser/content/content-UITour.js", true);
     mm.loadFrameScript("chrome://global/content/manifestMessages.js", true);
-    mm.loadFrameScript("chrome://global/content/viewSource-content.js", true);
 
     window.messageManager.addMessageListener("Browser:LoadURI", RedirectLoad);
 

browser/components/sessionstore/SessionStore.jsm

@@ -158,6 +158,8 @@ XPCOMUtils.defineLazyModuleGetter(this, "TabStateFlusher",
   "resource:///modules/sessionstore/TabStateFlusher.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "Utils",
   "resource:///modules/sessionstore/Utils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "ViewSourceBrowser",
+  "resource://gre/modules/ViewSourceBrowser.jsm");
 
 /**
  * |true| if we are in debug mode, |false| otherwise.
@@ -2817,6 +2819,12 @@ let SessionStoreInternal = {
     }
     tabbrowser.updateBrowserRemotenessByURL(browser, uri);
 
+    // If the restored browser wants to show view source content, start up a
+    // view source browser that will load the required frame script.
+    if (uri && ViewSourceBrowser.isViewSource(uri)) {
+      new ViewSourceBrowser(browser);
+    }
+
     // Start a new epoch to discard all frame script messages relating to a
     // previous epoch. All async messages that are still on their way to chrome
     // will be ignored and don't override any tab data set when restoring.

toolkit/components/viewsource/ViewSourceBrowser.jsm

@@ -25,8 +25,14 @@ const BUNDLE_URL = "chrome://global/locale/viewSource.properties";
 const MARK_SELECTION_START = "\uFDD0";
 const MARK_SELECTION_END = "\uFDEF";
 
+const FRAME_SCRIPT = "chrome://global/content/viewSource-content.js";
+
 this.EXPORTED_SYMBOLS = ["ViewSourceBrowser"];
 
+// Keep a set of browsers we've seen before, so we can load our frame script as
+// needed into any new ones.
+let gKnownBrowsers = new WeakSet();
+
 /**
  * ViewSourceBrowser manages the view source <browser> from the chrome side.
  * It's companion frame script, viewSource-content.js, needs to be loaded as a
@@ -37,9 +43,8 @@ this.EXPORTED_SYMBOLS = ["ViewSourceBrowser"];
  * The page script takes care of loading the companion frame script.
  *
  * For a view source tab (or some other non-window case), an instance of this is
- * created by viewSourceUtils.js to wrap the <browser>.  The caller that manages
- * the <browser> is responsible for ensuring the companion frame script has been
- * loaded.
+ * created by viewSourceUtils.js to wrap the <browser>.  The frame script will
+ * be loaded by this module at construction time.
  */
 this.ViewSourceBrowser = function ViewSourceBrowser(aBrowser) {
   this._browser = aBrowser;
@@ -83,6 +88,14 @@ ViewSourceBrowser.prototype = {
     this.messages.forEach((msgName) => {
       this.mm.addMessageListener(msgName, this);
     });
+
+    // If we have a known <browser> already, load the frame script here.  This
+    // is not true for the window case, as the element does not exist until the
+    // XUL document loads.  For that case, the frame script is loaded by
+    // viewSource.js.
+    if (this._browser) {
+      this.loadFrameScript();
+    }
   },
 
   /**
@@ -95,6 +108,16 @@ ViewSourceBrowser.prototype = {
     });
   },
 
+  /**
+   * For a new browser we've not seen before, load the frame script.
+   */
+  loadFrameScript() {
+    if (!gKnownBrowsers.has(this.browser)) {
+      gKnownBrowsers.add(this.browser);
+      this.mm.loadFrameScript(FRAME_SCRIPT, false);
+    }
+  },
+
   /**
    * Anything added to the messages array will get handled here, and should
    * get dispatched to a specific function for the message name.
@@ -652,3 +675,13 @@ ViewSourceBrowser.prototype = {
   },
 
 };
+
+/**
+ * Helper to decide if a URI maps to view source content.
+ * @param uri
+ *        String containing the URI
+ */
+ViewSourceBrowser.isViewSource = function(uri) {
+  return uri.startsWith("view-source:") ||
+         (uri.startsWith("data:") && uri.includes("MathML"));
+};

toolkit/components/viewsource/content/viewSourceUtils.js

@@ -66,9 +66,7 @@ var gViewSourceUtils = {
 
   /**
    * Displays view source in the provided <browser>.  This allows for non-window
-   * display methods, such as a tab from Firefox.  The caller that manages
-   * the <browser> is responsible for ensuring the companion frame script,
-   * viewSource-content.js, has been loaded for the <browser>.
+   * display methods, such as a tab from Firefox.
    *
    * @param aArgs
    *        An object with the following properties:
@@ -95,9 +93,7 @@ var gViewSourceUtils = {
   /**
    * Displays view source for a selection from some document in the provided
    * <browser>.  This allows for non-window display methods, such as a tab from
-   * Firefox.  The caller that manages the <browser> is responsible for ensuring
-   * the companion frame script, viewSource-content.js, has been loaded for the
-   * <browser>.
+   * Firefox.
    *
    * @param aSelection
    *        A Selection object for the content of interest.
@@ -112,9 +108,7 @@ var gViewSourceUtils = {
   /**
    * Displays view source for a MathML fragment from some document in the
    * provided <browser>.  This allows for non-window display methods,  such as a
-   * tab from Firefox.  The caller that manages the <browser> is responsible for
-   * ensuring the companion frame script, viewSource-content.js, has been loaded
-   * for the <browser>.
+   * tab from Firefox.
    *
    * @param aNode
    *        Some element within the fragment of interest.