Context menu on views must show on mouse down for non-WIN.

ui/views/widget/widget.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 "ui/views/widget/widget.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
@@ skipping 43 matching lines @@
 // Finally, make a default one.
 NativeWidget* CreateNativeWidget(NativeWidget* native_widget,
                                  internal::NativeWidgetDelegate* delegate) {
   if (!native_widget) {
     native_widget =
         internal::NativeWidgetPrivate::CreateNativeWidget(delegate);
   }
   return native_widget;
 }
 
+class PostMousePressedProcessor : public WidgetObserver {

[sky, 2013/03/21 22:17:48]

How about declaring this as an inner class (you can keep all this here, just put
class PostMousePressedProcessor; in Widget). That way you don't need to expose
set_is_mouse_button_pressed.

[varunjain, 2013/03/21 22:47:14]

Done.

+ public:
+  explicit PostMousePressedProcessor(views::Widget* owner) : owner_(owner) {
+    owner_->AddObserver(this);
+  }
+
+  virtual ~PostMousePressedProcessor() {
+    if (owner_) {
+      owner_->RemoveObserver(this);
+      owner_ = NULL;
+    }
+  }
+
+  void DoPostMousePressedProcessing() {
+    // Make sure we're still visible before we attempt capture as the mouse
+    // press processing may have made the window hide (as happens with menus).
+    if (!owner_ || !owner_->IsVisible())
+      return;
+
+    owner_->set_is_mouse_button_pressed(true);
+
+    // OnNativeWidgetDestroying also notifies all
+    // WidgetObservers::OnWidgetDestroying. So we can be sure that if |owner_|
+    // is non-NULL, |owner_->native_widget_| will also be non-NULL.
+    if (!owner_->native_widget_private()->HasCapture())
+      owner_->native_widget_private()->SetCapture();
+  }
+
+  // Overridden from WidgetObserver.
+  virtual void OnWidgetDestroying(Widget* widget) OVERRIDE {
+    if (owner_) {

[sky, 2013/03/21 22:17:48]

Consolidate this and 71-74.

[varunjain, 2013/03/21 22:47:14]

Done.

+      owner_->RemoveObserver(this);
+      owner_ = NULL;
+    }
+  }
+
+ private:
+  views::Widget* owner_;
+
+  DISALLOW_COPY_AND_ASSIGN(PostMousePressedProcessor);
+};
+
 }  // namespace
 
 // This class is used to keep track of the event a Widget is processing, and
 // restore any previously active event afterwards.
 class ScopedEvent {
  public:
   ScopedEvent(Widget* widget, const ui::Event& event)
       : widget_(widget),
         event_(&event) {
     widget->event_stack_.push(this);
@@ skipping 1062 matching lines @@
 void Widget::OnKeyEvent(ui::KeyEvent* event) {
   ScopedEvent scoped(this, *event);
   static_cast<internal::RootView*>(GetRootView())->
       DispatchKeyEvent(event);
 }
 
 void Widget::OnMouseEvent(ui::MouseEvent* event) {
   ScopedEvent scoped(this, *event);
   View* root_view = GetRootView();
   switch (event->type()) {
-    case ui::ET_MOUSE_PRESSED:
+    case ui::ET_MOUSE_PRESSED: {
       last_mouse_event_was_move_ = false;
-      // Make sure we're still visible before we attempt capture as the mouse
-      // press processing may have made the window hide (as happens with menus).
-      if (root_view && root_view->OnMousePressed(*event) && IsVisible()) {
-        is_mouse_button_pressed_ = true;
-        if (!native_widget_->HasCapture())
-          native_widget_->SetCapture();
+
+      // We may get deleted by the time we return from OnMousePressed. So we
+      // use an observer to do capture after OnMousePressed in a safe way.
+      PostMousePressedProcessor post_mouse_pressed_processor(this);
+      if (root_view && root_view->OnMousePressed(*event)) {
+        post_mouse_pressed_processor.DoPostMousePressedProcessing();
         event->SetHandled();
       }
       return;
+    }
     case ui::ET_MOUSE_RELEASED:
       last_mouse_event_was_move_ = false;
       is_mouse_button_pressed_ = false;
       // Release capture first, to avoid confusion if OnMouseReleased blocks.
       if (native_widget_->HasCapture() &&
           ShouldReleaseCaptureOnMouseReleased()) {
         native_widget_->ReleaseCapture();
       }
       if (root_view)
         root_view->OnMouseReleased(*event);
@@ skipping 254 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // internal::NativeWidgetPrivate, NativeWidget implementation:
 
 internal::NativeWidgetPrivate* NativeWidgetPrivate::AsNativeWidgetPrivate() {
   return this;
 }
 
 }  // namespace internal
 }  // namespace views