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

chrome/browser/chromeos/login/webui_login_view.cc

Index: chrome/browser/chromeos/login/webui_login_view.cc
diff --git a/chrome/browser/chromeos/login/webui_login_view.cc b/chrome/browser/chromeos/login/webui_login_view.cc
index 3480c7f8113e4780daaabdbf0a6b83c99bf5f730..e4e888212885ecc9af87c607f23bd47fe0b12eca 100644
--- a/chrome/browser/chromeos/login/webui_login_view.cc
+++ b/chrome/browser/chromeos/login/webui_login_view.cc
@@ -115,6 +115,7 @@ WebUILoginView::WebUILoginView()
       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,
@@ -279,18 +280,7 @@ 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,
@@ -301,7 +291,17 @@ void WebUILoginView::Observe(int type,
     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;
@@ -349,6 +349,31 @@ bool WebUILoginView::TakeFocus(bool reverse) {
   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);