Notifying the Out of Process Renderer about Visibility Change of a Remote Frame

third_party/WebKit/Source/core/frame/RemoteFrameView.cpp

 // Copyright 2014 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 "config.h"
 #include "core/frame/RemoteFrameView.h"
 
 #include "core/frame/RemoteFrame.h"
 #include "core/layout/LayoutPart.h"
 
@@ skipping 38 matching lines @@
     Widget::setFrameRect(newRect);
 
     frameRectsChanged();
 }
 
 void RemoteFrameView::frameRectsChanged()
 {
     m_remoteFrame->frameRectsChanged(frameRect());
 }
 
+void RemoteFrameView::hide()
+{
+    setSelfVisible(false);
+
+    Widget::hide();
+
+    m_remoteFrame->visibilityChanged(false);
+}
+
+void RemoteFrameView::show()
+{
+    setSelfVisible(true);
+
+    Widget::show();
+
+    m_remoteFrame->visibilityChanged(true);
+}
+
+void RemoteFrameView::setParentVisible(bool visible)
+{
+    if (isParentVisible() == visible)
+        return;
+
+    Widget::setParentVisible(visible);
+
+    if (!isSelfVisible())
+        return;
+
+    m_remoteFrame->visibilityChanged(isVisible());

[dcheng, 2015/12/02 00:15:05]

I'm having trouble convincing myself this is correct.

Why is it OK to omit this callback if !isSelfVisible() == false?

[EhsanK, 2015/12/07 16:10:15]

I actually inferred the logic from here:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

What I thought to be true was that if this Widget is set to invisible, then
setting the parent to visible/invisible should not change anything. Please help
me understand the error. Thanks!

+}
+
 DEFINE_TRACE(RemoteFrameView)
 {
     visitor->trace(m_remoteFrame);
     Widget::trace(visitor);
 }
 
 } // namespace blink