[cros] Change how login-prompt-visible signal is emitted when accelerated compositing is enabled.

chrome/browser/chromeos/login/webui_login_view.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chromeos/login/webui_login_view.h"
 
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray.h"
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 97 matching lines @@
 
 namespace chromeos {
 
 // WebUILoginView public: ------------------------------------------------------
 
 WebUILoginView::WebUILoginView()
     : webui_login_(NULL),
       login_window_(NULL),
       host_window_frozen_(false),
       login_page_is_loaded_(false),
+      login_prompt_visible_notified_(false),
       should_emit_login_prompt_visible_(true) {
 
   registrar_.Add(this,
                  chrome::NOTIFICATION_LOGIN_WEBUI_READY,
                  content::NotificationService::AllSources());
   registrar_.Add(this,
                  chrome::NOTIFICATION_LOGIN_USER_IMAGES_LOADED,
                  content::NotificationService::AllSources());
   registrar_.Add(this,
                  chrome::NOTIFICATION_LOGIN_NETWORK_ERROR_SHOWN,
@@ skipping 144 matching lines @@
 }
 
 void WebUILoginView::OnTabMainFrameLoaded() {
   VLOG(1) << "WebUI login main frame loaded.";
 }
 
 void WebUILoginView::OnTabMainFrameRender() {
   if (!login_page_is_loaded_)
     return;
 
-  VLOG(1) << "WebUI login main frame rendered.";
-  tab_watcher_.reset();
-
-  if (should_emit_login_prompt_visible_) {
-    chromeos::DBusThreadManager::Get()->GetSessionManagerClient()->
-        EmitLoginPromptVisible();
-  }
-
-  OobeUI* oobe_ui = static_cast<OobeUI*>(GetWebUI()->GetController());
-  // Notify OOBE that the login frame has been rendered. Currently
-  // this is used to start camera presence check.
-  oobe_ui->OnLoginPromptVisible();
+  OnLoginPromptVisible();
 }
 
 void WebUILoginView::Observe(int type,
                              const content::NotificationSource& source,
                              const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_LOGIN_WEBUI_READY:
     case chrome::NOTIFICATION_LOGIN_USER_IMAGES_LOADED:
     case chrome::NOTIFICATION_LOGIN_NETWORK_ERROR_SHOWN:
     case chrome::NOTIFICATION_WIZARD_FIRST_SCREEN_SHOWN:
+      VLOG(1) << "===================== WebUI login ready notification";
       login_page_is_loaded_ = true;
+      // In case of accelerated compositing being enabled at sign in screen,
+      // no more OnTabMainFrameRender() calls are being made after
+      // OnTabMainFrameLoaded() or after any of these notifications is received.
+      // So mark sign in screen as visible now.
+      // TODO(nkostylev): Improve OOBE case as with accelerated compositing
+      // using NOTIFICATION_WIZARD_FIRST_SCREEN_SHOWN is not correct cause
+      // it fires login-prompt-visible before login-prompt-ready.
+      if (IsAcceleratedCompositingEnabled())
+        OnLoginPromptVisible();
       break;
     default:
       NOTREACHED() << "Unexpected notification " << type;
   }
 }
 
 // WebUILoginView private: -----------------------------------------------------
 
 bool WebUILoginView::HandleContextMenu(
     const content::ContextMenuParams& params) {
@@ skipping 27 matching lines @@
   ash::SystemTray* tray = ash::Shell::GetInstance()->tray();
   if (tray && tray->GetWidget()->IsVisible()) {
     tray->SetNextFocusableView(this);
     ash::Shell::GetInstance()->RotateFocus(reverse ? ash::Shell::BACKWARD :
                                                      ash::Shell::FORWARD);
   }
 
   return true;
 }
 
+bool WebUILoginView::IsAcceleratedCompositingEnabled() {
+  // TODO(nkostylev): Temporary check, should be modified once
+  // http://crbug.com/116800 is fixed and if this switch is removed.
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  return command_line.HasSwitch(switches::kAllowWebUICompositing);

[Daniel Erat, 2012/05/28 15:20:53]

is there any risk that this might not get updated when accelerated compositing
is turned on by default?  if so, any way that this can be made safer (e.g. move
this utility function somewhere else so there's a single path used by all the
code that needs to check the flag)?  if the flag will be removed in the same
changelist that turns it on, it's probably okay.

[Nikita (slow), 2012/05/28 15:55:05]

I've actually thought that when accelerated compositing will  be enabled for all
WebUI, this flag meaning would get flipped so it will require update of this
code as well.

+}
+
+void WebUILoginView::OnLoginPromptVisible() {
+  if (login_prompt_visible_notified_)
+    return;
+
+  login_prompt_visible_notified_ = true;
+  tab_watcher_.reset();
+
+  if (should_emit_login_prompt_visible_) {
+    chromeos::DBusThreadManager::Get()->GetSessionManagerClient()->
+        EmitLoginPromptVisible();
+  }
+
+  OobeUI* oobe_ui = static_cast<OobeUI*>(GetWebUI()->GetController());
+  // Notify OOBE that the login frame has been rendered. Currently
+  // this is used to start camera presence check.
+  oobe_ui->OnLoginPromptVisible();
+}
+
 void WebUILoginView::ReturnFocus(bool reverse) {
   // Return the focus to the web contents.
   webui_login_->web_contents()->FocusThroughTabTraversal(reverse);
   GetWidget()->Activate();
 }
 
 }  // namespace chromeos