Cleanup RemotePlatformLayer when disconnecting RemoteFrame.

Source/core/frame/RemoteFrame.cpp

Index: Source/core/frame/RemoteFrame.cpp
diff --git a/Source/core/frame/RemoteFrame.cpp b/Source/core/frame/RemoteFrame.cpp
index 7b07fdca6504eb37b51d917e4a7b90034cf19509..9e92ada976dceb63462e2827f70721a768e73c9c 100644
--- a/Source/core/frame/RemoteFrame.cpp
+++ b/Source/core/frame/RemoteFrame.cpp
@@ -11,7 +11,11 @@
 #include "core/frame/RemoteFrameClient.h"
 #include "core/frame/RemoteFrameView.h"
 #include "core/html/HTMLFrameOwnerElement.h"
+#include "core/rendering/RenderLayer.h"
+#include "core/rendering/RenderPart.h"
+#include "platform/graphics/GraphicsLayer.h"
 #include "platform/weborigin/SecurityPolicy.h"
+#include "public/platform/WebLayer.h"
 
 namespace blink {
 
@@ -20,6 +24,7 @@ inline RemoteFrame::RemoteFrame(RemoteFrameClient* client, FrameHost* host, Fram
     , m_securityContext(RemoteSecurityContext::create())
     , m_domWindow(RemoteDOMWindow::create(*this))
     , m_windowProxyManager(WindowProxyManager::create(*this))
+    , m_remotePlatformLayer(nullptr)
 {
 }
 
@@ -79,6 +84,13 @@ RemoteSecurityContext* RemoteFrame::securityContext() const
     return m_securityContext.get();
 }
 
+void RemoteFrame::disconnectOwnerElement()
+{
+    if (owner() && owner()->isLocal())

[dcheng, 2015/02/03 22:08:37]

Why do we do this work here instead of, say, RemoteFrame::detach()? Is there a
corresponding cleanup step for LocalFrames that we can mirror here?

Also, would it make more sense for this check to be something like:

if (m_remotePlatformLayer)
    setRemotePlatformLayer(nullptr);

[lfg, 2015/02/03 22:54:50]

It needs to run on both WebFrame::swap(), as well as detach(). It doesn't look
like there's any other place that would fit. (LocalFrame also have a
disconnectOwnerElement() override to do some cleanups).
This makes sense, changed.

[dcheng, 2015/02/04 00:02:23]

Can we add a comment to this effect? It's not immediately obvious to the reader
that that's the requirement for this logic belonging here. In addition, I think
there is a high chance that WebFrame::swap() will end up calling detach() on the
frames (but obviously that's still in flux).

+        setRemotePlatformLayer(nullptr);
+    Frame::disconnectOwnerElement();
+}
+
 void RemoteFrame::forwardInputEvent(Event* event)
 {
     remoteFrameClient()->forwardInputEvent(event);
@@ -108,4 +120,18 @@ RemoteFrameClient* RemoteFrame::remoteFrameClient() const
     return static_cast<RemoteFrameClient*>(client());
 }
 
+void RemoteFrame::setRemotePlatformLayer(WebLayer* layer)
+{
+    if (m_remotePlatformLayer)
+        GraphicsLayer::unregisterContentsLayer(m_remotePlatformLayer);
+    m_remotePlatformLayer = layer;
+    if (m_remotePlatformLayer)
+        GraphicsLayer::registerContentsLayer(layer);
+
+    ASSERT(owner());
+    toHTMLFrameOwnerElement(owner())->setNeedsCompositingUpdate();
+    if (RenderPart* renderer = ownerRenderer())
+        renderer->layer()->updateSelfPaintingLayer();
+}
+
 } // namespace blink