Fix a couple crashes.

- chromium-os:4237 is a crash where button listener is released before
  the button. And there could be such a case in PanelController where
  close button and its listener is not coupled as other part of the code.
  Potentially, a PanelController as the button listener could be released
  before the button. The fix is to use the TitleCotnentView as button listener
  and because it's the parent view of the button, it is always valid for
  the life time of the button.
- Fix a crash in BrowserTabStripController::CreateNewTab when trying to dig
  out cause for 4237. It could happen that user clicks quickly on close tab
  and then on new tab button and model_->GetSelectedTabContents() returns
  NULL;

BUG=chromium-os:4237
TEST=No more crashes coming in as in chromius-os:4237.

Review URL: http://codereview.chromium.org/2803024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50990 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 23 insertions, 10 deletions

diff --git a/chrome/browser/chromeos/frame/panel_controller.cc b/chrome/browser/chromeos/frame/panel_controller.cc
index 7d0e5f3..4cfcea1 100644
--- a/chrome/browser/chromeos/frame/panel_controller.cc
+++ b/chrome/browser/chromeos/frame/panel_controller.cc
@@ -271,10 +271,9 @@ void PanelController::Close() {
   }
 }
 
-void PanelController::ButtonPressed(
-    views::Button* sender, const views::Event& event) {
+void PanelController::OnCloseButtonPressed() {
   DCHECK(title_content_);
-  if (title_window_ && sender == title_content_->close_button()) {
+  if (title_window_) {
     if (delegate_)
       delegate_->ClosePanel();
     Close();
@@ -285,7 +284,7 @@ PanelController::TitleContentView::TitleContentView(
     PanelController* panel_controller)
         : panel_controller_(panel_controller) {
   InitializeResources();
-  close_button_ = new views::ImageButton(panel_controller_);
+  close_button_ = new views::ImageButton(this);
   close_button_->SetImage(views::CustomButton::BS_NORMAL, close_button_n);
   close_button_->SetImage(views::CustomButton::BS_HOT, close_button_h);
   close_button_->SetImage(views::CustomButton::BS_PUSHED, close_button_p);
@@ -363,4 +362,10 @@ void PanelController::TitleContentView::OnClose() {
   panel_controller_ = NULL;
 }
 
+void PanelController::TitleContentView::ButtonPressed(
+    views::Button* sender, const views::Event& event) {
+  if (panel_controller_ && sender == close_button_)
+    panel_controller_->OnCloseButtonPressed();
+}
+
 }  // namespace chromeos
diff --git a/chrome/browser/chromeos/frame/panel_controller.h b/chrome/browser/chromeos/frame/panel_controller.h
index 58a1660..63b1898 100644
--- a/chrome/browser/chromeos/frame/panel_controller.h
+++ b/chrome/browser/chromeos/frame/panel_controller.h
@@ -25,7 +25,7 @@ class WidgetGtk;
 namespace chromeos {
 
 // Controls interactions with the WM for popups / panels.
-class PanelController : public views::ButtonListener {
+class PanelController {
  public:
   enum State {
     INITIAL,
@@ -66,11 +66,9 @@ class PanelController : public views::ButtonListener {
 
   void SetState(State state);
 
-  // ButtonListener methods.
-  virtual void ButtonPressed(views::Button* sender, const views::Event& event);
-
  private:
-  class TitleContentView : public views::View {
+  class TitleContentView : public views::View,
+                           public views::ButtonListener {
    public:
     explicit TitleContentView(PanelController* panelController);
     virtual ~TitleContentView() {}
@@ -86,6 +84,9 @@ class PanelController : public views::ButtonListener {
     views::Label* title_label() { return title_label_; }
     views::ImageButton* close_button() { return close_button_; }
 
+    // ButtonListener methods.
+    virtual void ButtonPressed(views::Button* sender,
+                               const views::Event& event);
    private:
     views::ImageView* title_icon_;
     views::Label* title_label_;
@@ -94,6 +95,9 @@ class PanelController : public views::ButtonListener {
     DISALLOW_COPY_AND_ASSIGN(TitleContentView);
   };
 
+  // Called from TitleContentView's ButtonPressed handler.
+  void OnCloseButtonPressed();
+
   // Dispatches client events to PanelController instances
   static bool OnPanelClientEvent(
       GtkWidget* widget,
diff --git a/chrome/browser/views/tabs/browser_tab_strip_controller.cc b/chrome/browser/views/tabs/browser_tab_strip_controller.cc
index dcb41dd..69af6fa 100644
--- a/chrome/browser/views/tabs/browser_tab_strip_controller.cc
+++ b/chrome/browser/views/tabs/browser_tab_strip_controller.cc
@@ -276,7 +276,11 @@ void BrowserTabStripController::CreateNewTab() {
   UserMetrics::RecordAction(UserMetricsAction("NewTab_Button"),
                             model_->profile());
 
-  Browser* browser = model_->GetSelectedTabContents()->delegate()->GetBrowser();
+  TabContents* selected_tab = model_->GetSelectedTabContents();
+  if (!selected_tab)
+    return;
+
+  Browser* browser = selected_tab->delegate()->GetBrowser();
   if (browser->OpenAppsPanelAsNewTab())
     return;