Initialize DOMUI handlers if the DOM itself is re-used

Back/forward causes a page navigation, triggering a new DOMUI to be created. Since the page is the same, however, WebKit doesn't actually do a navigation, and the DOM remains intact, so the onload handler doesn't fire and cause the newly-created DOMUI to be initialized.

This change notifies the DOMUI object when it has been bound to a RenderView that may have an existing DOM on the HTML/JS side, so that it can tell the page to re-trigger initialization if necessary.

BUG=60768
TEST=Open DOMUI prefs, go to another pref section, press the Back button, then try to change the search engines.

Review URL: http://codereview.chromium.org/5120005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@67611 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 44 insertions, 0 deletions

diff --git a/chrome/browser/dom_ui/dom_ui.h b/chrome/browser/dom_ui/dom_ui.h
index 5e76b7c..a74186d 100644
--- a/chrome/browser/dom_ui/dom_ui.h
+++ b/chrome/browser/dom_ui/dom_ui.h
@@ -42,6 +42,17 @@ class DOMUI {
   // page.
   virtual void RenderViewReused(RenderViewHost* render_view_host) {}
 
+  // Called when this becomes the active DOMUI instance for a re-used
+  // RenderView; this is the point at which this DOMUI instance will receive
+  // DOM messages instead of the previous DOMUI instance.
+  //
+  // If a DOMUI instance has code that is usually triggered from a JavaScript
+  // onload handler, this should be overridden to check to see if the web page's
+  // DOM is still intact (e.g., due to a back/forward navigation that remains
+  // within the same page), and if so trigger that code manually since onload
+  // won't be run in that case.
+  virtual void DidBecomeActiveForReusedRenderView() {}
+
   // Called from TabContents.
   virtual void ProcessDOMUIMessage(const ViewHostMsg_DomMessage_Params& params);
 
diff --git a/chrome/browser/dom_ui/options/options_ui.cc b/chrome/browser/dom_ui/options/options_ui.cc
index 44d3b5d..2b250e7 100644
--- a/chrome/browser/dom_ui/options/options_ui.cc
+++ b/chrome/browser/dom_ui/options/options_ui.cc
@@ -231,6 +231,18 @@ void OptionsUI::RenderViewCreated(RenderViewHost* render_view_host) {
   DOMUI::RenderViewCreated(render_view_host);
 }
 
+void OptionsUI::DidBecomeActiveForReusedRenderView() {
+  // When the renderer is re-used (e.g., for back/forward navigation within
+  // options), the handlers are torn down and rebuilt, so are no longer
+  // initialized, but the web page's DOM may remain intact, in which case onload
+  // won't fire to initilize the handlers. To make sure initialization always
+  // happens, call reinitializeCore (which is a no-op unless the DOM was already
+  // initialized).
+  CallJavascriptFunction(L"OptionsPage.reinitializeCore");
+
+  DOMUI::DidBecomeActiveForReusedRenderView();
+}
+
 // static
 RefCountedMemory* OptionsUI::GetFaviconResourceBytes() {
   return ResourceBundle::GetSharedInstance().
diff --git a/chrome/browser/dom_ui/options/options_ui.h b/chrome/browser/dom_ui/options/options_ui.h
index fafe972..fbc55e6 100644
--- a/chrome/browser/dom_ui/options/options_ui.h
+++ b/chrome/browser/dom_ui/options/options_ui.h
@@ -82,6 +82,7 @@ class OptionsUI : public DOMUI {
 
   static RefCountedMemory* GetFaviconResourceBytes();
   void RenderViewCreated(RenderViewHost* render_view_host);
+  void DidBecomeActiveForReusedRenderView();
 
   void InitializeHandlers();
 
diff --git a/chrome/browser/resources/options/options_page.js b/chrome/browser/resources/options/options_page.js
index af66889..18b700e 100644
--- a/chrome/browser/resources/options/options_page.js
+++ b/chrome/browser/resources/options/options_page.js
@@ -37,6 +37,11 @@ cr.define('options', function() {
   OptionsPage.registeredOverlayPages_ = {};
 
   /**
+   * Whether or not |initialize| has been called.
+   */
+  OptionsPage.initialized_ = false;
+
+  /**
    * Shows a registered page. This handles both top-level pages and sub-pages.
    * @param {string} pageName Page name.
    */
@@ -207,6 +212,7 @@ cr.define('options', function() {
    */
   OptionsPage.initialize = function() {
     chrome.send('coreOptionsInitialize');
+    this.initialized_ = true;
 
     // Set up the overlay sheet. Clicks on the visible part of the parent page
     // should close the overlay, not fall through to the parent page.
@@ -217,6 +223,18 @@ cr.define('options', function() {
     }
   };
 
+  /**
+   * Re-initializes the C++ handlers if necessary. This is called if the
+   * handlers are torn down and recreated but the DOM may not have been (in
+   * which case |initialize| won't be called again). If |initialize| hasn't been
+   * called, this does nothing (since it will be later, once the DOM has
+   * finished loading).
+   */
+  OptionsPage.reinitializeCore = function() {
+    if (this.initialized_)
+      chrome.send('coreOptionsInitialize');
+  }
+
   OptionsPage.prototype = {
     __proto__: cr.EventTarget.prototype,
 
diff --git a/chrome/browser/tab_contents/render_view_host_manager.cc b/chrome/browser/tab_contents/render_view_host_manager.cc
index 664b7f5..c9e6373 100644
--- a/chrome/browser/tab_contents/render_view_host_manager.cc
+++ b/chrome/browser/tab_contents/render_view_host_manager.cc
@@ -495,6 +495,8 @@ void RenderViewHostManager::CommitPending() {
 
   // Next commit the DOM UI, if any.
   dom_ui_.swap(pending_dom_ui_);
+  if (dom_ui_.get() && pending_dom_ui_.get() && !pending_render_view_host_)
+    dom_ui_->DidBecomeActiveForReusedRenderView();
   pending_dom_ui_.reset();
 
   // It's possible for the pending_render_view_host_ to be NULL when we aren't