Reland fast tab closure behind a flag

chrome/browser/ui/browser.cc

Index: chrome/browser/ui/browser.cc
diff --git a/chrome/browser/ui/browser.cc b/chrome/browser/ui/browser.cc
index 22df809cdc2fd0730f4ccca2e2a721531ea31519..11048c86a33e17fd091c8c2f59a8589472c76d68 100644
--- a/chrome/browser/ui/browser.cc
+++ b/chrome/browser/ui/browser.cc
@@ -108,6 +108,7 @@
 #include "chrome/browser/ui/chrome_pages.h"
 #include "chrome/browser/ui/chrome_select_file_policy.h"
 #include "chrome/browser/ui/extensions/shell_window.h"
+#include "chrome/browser/ui/fast_unload_controller.h"
 #include "chrome/browser/ui/find_bar/find_bar.h"
 #include "chrome/browser/ui/find_bar/find_bar_controller.h"
 #include "chrome/browser/ui/find_bar/find_tab_helper.h"
@@ -233,6 +234,12 @@ BrowserWindow* CreateBrowserWindow(Browser* browser) {
   return BrowserWindow::CreateBrowserWindow(browser);
 }
 
+// Is the fast tab unload experiment enabled?
+bool FastTabUnloadEnabled() {

[sky, 2013/06/27 16:13:16]

IsFastTabUnloadEnabled?

+  return CommandLine::ForCurrentProcess()->HasSwitch(
+        switches::kEnableFastUnload);
+}
+
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -332,7 +339,6 @@ Browser::Browser(const CreateParams& params)
       initial_show_state_(params.initial_show_state),
       is_session_restore_(params.is_session_restore),
       host_desktop_type_(params.host_desktop_type),
-      unload_controller_(new chrome::UnloadController(this)),
       weak_factory_(this),
       content_setting_bubble_model_delegate_(
           new BrowserContentSettingBubbleModelDelegate(this)),
@@ -348,6 +354,12 @@ Browser::Browser(const CreateParams& params)
   // from opening at all, but the path that triggered it should be fixed.
   CHECK(IncognitoModePrefs::CanOpenBrowser(profile_));
 
+  // TODO(jeremy): Move to initializer list once flag is removed.
+  if (FastTabUnloadEnabled())
+    fast_unload_controller_.reset(new chrome::FastUnloadController(this));
+  else
+    unload_controller_.reset(new chrome::UnloadController(this));
+
   if (!app_name_.empty())
     chrome::RegisterAppPrefs(app_name_, profile_);
   tab_strip_model_->AddObserver(this);
@@ -585,7 +597,15 @@ bool Browser::ShouldCloseWindow() {
   if (!CanCloseWithInProgressDownloads())
     return false;
 
-  return unload_controller_->ShouldCloseWindow();
+  if (FastTabUnloadEnabled())
+    return fast_unload_controller_->ShouldCloseWindow();
+  else

[sky, 2013/06/27 16:13:16]

nit: no else after a return.

+    return unload_controller_->ShouldCloseWindow();
+}
+
+bool Browser::HasCompletedUnloadProcessing() const {
+  DCHECK(FastTabUnloadEnabled());
+  return fast_unload_controller_->HasCompletedUnloadProcessing();
 }
 
 bool Browser::HasCompletedUnloadProcessing() const {
@@ -593,7 +613,10 @@ bool Browser::HasCompletedUnloadProcessing() const {
 }
 
 bool Browser::IsAttemptingToCloseBrowser() const {
-  return unload_controller_->is_attempting_to_close_browser();
+  if (FastTabUnloadEnabled())
+    return fast_unload_controller_->is_attempting_to_close_browser();
+  else

[sky, 2013/06/27 16:13:16]

same nit here.

+    return unload_controller_->is_attempting_to_close_browser();
 }
 
 void Browser::OnWindowClosing() {
@@ -636,7 +659,8 @@ void Browser::OnWindowClosing() {
       content::Source<Browser>(this),
       content::NotificationService::NoDetails());
 
-  tab_strip_model_->CloseAllTabs();
+  if (!FastTabUnloadEnabled())
+    tab_strip_model_->CloseAllTabs();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -1174,7 +1198,10 @@ void Browser::HandleKeyboardEvent(content::WebContents* source,
 }
 
 bool Browser::TabsNeedBeforeUnloadFired() {
-  return unload_controller_->TabsNeedBeforeUnloadFired();
+  if (FastTabUnloadEnabled())
+    return fast_unload_controller_->TabsNeedBeforeUnloadFired();
+  else

[sky, 2013/06/27 16:13:16]

and here.

+    return unload_controller_->TabsNeedBeforeUnloadFired();
 }
 
 bool Browser::IsMouseLocked() const {
@@ -1310,7 +1337,13 @@ void Browser::LoadingStateChanged(WebContents* source) {
 }
 
 void Browser::CloseContents(WebContents* source) {
-  if (unload_controller_->CanCloseContents(source))
+  bool can_close_contents;
+  if (FastTabUnloadEnabled())
+    can_close_contents = fast_unload_controller_->CanCloseContents(source);
+  else
+    can_close_contents = unload_controller_->CanCloseContents(source);
+
+  if (can_close_contents)
     chrome::CloseWebContents(this, source, true);
 }
 
@@ -1373,8 +1406,12 @@ gfx::Rect Browser::GetRootWindowResizerRect() const {
 void Browser::BeforeUnloadFired(WebContents* web_contents,
                                 bool proceed,
                                 bool* proceed_to_fire_unload) {
-  *proceed_to_fire_unload =
-      unload_controller_->BeforeUnloadFired(web_contents, proceed);
+  if (FastTabUnloadEnabled())

[sky, 2013/06/27 16:13:16]

nit: use {} for multi-line ones.

+    *proceed_to_fire_unload =
+        fast_unload_controller_->BeforeUnloadFired(web_contents, proceed);
+  else
+    *proceed_to_fire_unload =
+        unload_controller_->BeforeUnloadFired(web_contents, proceed);
 }
 
 bool Browser::ShouldFocusLocationBarByDefault(WebContents* source) {