3 files changed, 61 insertions, 22 deletions

diff --git a/chrome/browser/pref_member.h b/chrome/browser/pref_member.h
index 0c95c2f..2de76ab 100644
--- a/chrome/browser/pref_member.h
+++ b/chrome/browser/pref_member.h
@@ -120,6 +120,13 @@ class PrefMember : public subtle::PrefMemberBase {
     setting_value_ = false;
   }
 
+  // Set the value of the member variable if it is not managed.
+  void SetValueIfNotManaged(const ValueType& value) {
+    if (!IsManaged()) {
+      SetValue(value);
+    }
+  }
+
  protected:
   // This methods is used to do the actual sync with pref of the specified type.
   virtual void UpdatePref(const ValueType& value) = 0;
diff --git a/chrome/browser/views/options/general_page_view.cc b/chrome/browser/views/options/general_page_view.cc
index be464b4..afe4ae7 100644
--- a/chrome/browser/views/options/general_page_view.cc
+++ b/chrome/browser/views/options/general_page_view.cc
@@ -44,6 +44,9 @@ const SkColor kDefaultBrowserLabelColor = SkColorSetRGB(0, 135, 0);
 const SkColor kNotDefaultBrowserLabelColor = SkColorSetRGB(135, 0, 0);
 const int kHomePageTextfieldWidthChars = 40;
 
+bool IsNewTabUIURLString(const GURL& url) {
+  return url == GURL(chrome::kChromeUINewTabURL);
+}
 }  // namespace
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -384,19 +387,23 @@ void GeneralPageView::NotifyPrefChanged(const std::wstring* pref_name) {
   if (!pref_name ||
       *pref_name == prefs::kHomePageIsNewTabPage ||
       *pref_name == prefs::kHomePage) {
-    bool managed =
-        new_tab_page_is_home_page_.IsManaged() || homepage_.IsManaged();
-    bool homepage_valid = homepage_.GetValue() != chrome::kChromeUINewTabURL;
-    bool use_new_tab_page_for_homepage =
-        new_tab_page_is_home_page_.GetValue() || !homepage_valid;
-    homepage_use_newtab_radio_->SetChecked(use_new_tab_page_for_homepage);
-    homepage_use_newtab_radio_->SetEnabled(!managed);
-    homepage_use_url_radio_->SetChecked(!use_new_tab_page_for_homepage);
-    homepage_use_url_radio_->SetEnabled(!managed);
-
-    if (homepage_valid)
+    bool new_tab_page_is_home_page_managed =
+        new_tab_page_is_home_page_.IsManaged();
+    bool homepage_managed = homepage_.IsManaged();
+    bool homepage_url_is_new_tab =
+        IsNewTabUIURLString(GURL(homepage_.GetValue()));
+    bool homepage_is_new_tab = homepage_url_is_new_tab ||
+        new_tab_page_is_home_page_.GetValue();
+    // If HomepageIsNewTab is managed or
+    // Homepage is 'chrome://newtab' and managed, disable the radios.
+    bool disable_homepage_choice_buttons =
+        new_tab_page_is_home_page_managed ||
+        homepage_managed && homepage_url_is_new_tab;
+    if (!homepage_url_is_new_tab)
       homepage_use_url_textfield_->SetText(UTF8ToWide(homepage_.GetValue()));
-    EnableHomepageURLField(!managed && !use_new_tab_page_for_homepage);
+    UpdateHomepageIsNewTabRadio(
+        homepage_is_new_tab, !disable_homepage_choice_buttons);
+    EnableHomepageURLField(!homepage_is_new_tab);
   }
 
   if (!pref_name || *pref_name == prefs::kShowHomeButton) {
@@ -745,14 +752,37 @@ void GeneralPageView::UpdateHomepagePrefs() {
     URLFixerUpper::FixupURL(
        UTF16ToUTF8(homepage_use_url_textfield_->text()), std::string());
   bool new_tab_page_is_home_page = homepage_use_newtab_radio_->checked();
-  if (!homepage.is_valid() || homepage.spec() == chrome::kChromeUINewTabURL) {
+  if (IsNewTabUIURLString(homepage)) {  // 'chrome://newtab/'
+    // This should be handled differently than invalid URLs.
+    // When the control arrives here, then |homepage| contains
+    // 'chrome://newtab/', and the homepage preference contains the previous
+    // valid content of the textfield (fixed up), most likely
+    // 'chrome://newta/'. This has to be cleared, because keeping it makes no
+    // sense to the user.
+    new_tab_page_is_home_page = true;
+    homepage_.SetValueIfNotManaged(std::string());
+  } else if (!homepage.is_valid()) {
     new_tab_page_is_home_page = true;
+    // The URL is invalid either with a host (e.g. http://chr%mium.org)
+    // or without a host (e.g. http://). In case there is a host, then
+    // the URL is not cleared, saving a fragment of the URL to the
+    // preferences (e.g. http://chr in case the characters of the above example
+    // were typed by the user one by one).
+    // See bug 40996.
     if (!homepage.has_host())
-      homepage_.SetValue(std::string());
+      homepage_.SetValueIfNotManaged(std::string());
   } else {
-    homepage_.SetValue(homepage.spec());
+    homepage_.SetValueIfNotManaged(homepage.spec());
   }
-  new_tab_page_is_home_page_.SetValue(new_tab_page_is_home_page);
+  new_tab_page_is_home_page_.SetValueIfNotManaged(new_tab_page_is_home_page);
+}
+
+void GeneralPageView::UpdateHomepageIsNewTabRadio(bool homepage_is_new_tab,
+                                                  bool enabled) {
+  homepage_use_newtab_radio_->SetChecked(homepage_is_new_tab);
+  homepage_use_url_radio_->SetChecked(!homepage_is_new_tab);
+  homepage_use_newtab_radio_->SetEnabled(enabled);
+  homepage_use_url_radio_->SetEnabled(enabled);
 }
 
 void GeneralPageView::OnSelectionChanged() {
@@ -761,13 +791,11 @@ void GeneralPageView::OnSelectionChanged() {
 }
 
 void GeneralPageView::EnableHomepageURLField(bool enabled) {
-  if (enabled) {
-    homepage_use_url_textfield_->SetEnabled(true);
-    homepage_use_url_textfield_->SetReadOnly(false);
-  } else {
-    homepage_use_url_textfield_->SetEnabled(false);
-    homepage_use_url_textfield_->SetReadOnly(true);
+  if (homepage_.IsManaged()) {
+    enabled = false;
   }
+  homepage_use_url_textfield_->SetEnabled(enabled);
+  homepage_use_url_textfield_->SetReadOnly(!enabled);
 }
 
 void GeneralPageView::SetDefaultSearchProvider() {
diff --git a/chrome/browser/views/options/general_page_view.h b/chrome/browser/views/options/general_page_view.h
index 6cc4911..e827ecf 100644
--- a/chrome/browser/views/options/general_page_view.h
+++ b/chrome/browser/views/options/general_page_view.h
@@ -113,6 +113,10 @@ class GeneralPageView : public OptionsPageView,
   // Enables or disables the field for entering a custom homepage URL.
   void EnableHomepageURLField(bool enabled);
 
+  // Sets the state and enables/disables the radio buttons that control
+  // if the home page is the new tab page.
+  void UpdateHomepageIsNewTabRadio(bool homepage_is_new_tab, bool enabled);
+
   // Sets the default search provider for the selected item in the combobox.
   void SetDefaultSearchProvider();