Replace PlaceholderFrameOwner with RemoteBridgeFrameOwner.

Source/web/WebRemoteFrameImpl.h

Index: Source/web/WebRemoteFrameImpl.h
diff --git a/Source/web/WebRemoteFrameImpl.h b/Source/web/WebRemoteFrameImpl.h
index 24127ee4963f3c910d5205b7cbc553d7c2069476..359b2ebccf4ec41880847359a3a82cd2f6c6dc42 100644
--- a/Source/web/WebRemoteFrameImpl.h
+++ b/Source/web/WebRemoteFrameImpl.h
@@ -10,6 +10,7 @@
 #include "public/web/WebRemoteFrame.h"
 #include "public/web/WebRemoteFrameClient.h"
 #include "web/RemoteFrameClientImpl.h"
+#include "web/WebLocalFrameImpl.h"
 #include "wtf/HashMap.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/RefCounted.h"
@@ -20,21 +21,44 @@ class FrameHost;
 class FrameOwner;
 class RemoteFrame;
 
-// FIXME: This is just a placeholder frame owner to supply to RemoteFrame when
-// the parent is also a remote frame. Strictly speaking, this shouldn't be
-// necessary, since a remote frame shouldn't ever need to communicate with a
-// remote parent (there are no sandbox flags to retrieve in this case, nor can
-// the RemoteFrame itself load a document). In most circumstances, the check for
-// frame->owner() can be replaced with a check for frame->tree().parent(). Once
-// that's done, this class can be removed.
-class PlaceholderFrameOwner : public NoBaseWillBeGarbageCollectedFinalized<PlaceholderFrameOwner>, public FrameOwner {
-    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(PlaceholderFrameOwner);
+// Helper class to bridge communication for a frame with a remote parent.
+// Currently, it serves two purposes:
+// 1. Allows the local frame's loader to retrieve sandbox flags associated with
+//    its owner element in another process.
+// 2. Trigger a load event on its owner element once it finishes a load.
+class RemoteBridgeFrameOwner : public NoBaseWillBeGarbageCollectedFinalized<RemoteBridgeFrameOwner>, public FrameOwner {

[dcheng, 2015/02/11 21:57:24]

Perhaps we should move this to a new file? It seems a bit out of place in the
header.

[alexmos, 2015/02/11 22:39:45]

Done.

+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(RemoteBridgeFrameOwner);
+
 public:
-    virtual bool isLocal() const override;
-    virtual SandboxFlags sandboxFlags() const override;
+    static PassOwnPtrWillBeRawPtr<RemoteBridgeFrameOwner> create(PassRefPtrWillBeRawPtr<WebLocalFrameImpl> frame, SandboxFlags flags)
+    {
+        return adoptPtrWillBeNoop(new RemoteBridgeFrameOwner(frame, flags));
+    }
+
+    virtual bool isLocal() const override
+    {
+        return false;
+    }
+
+    virtual SandboxFlags sandboxFlags() const override
+    {
+        return m_sandboxFlags;
+    }
+
+    void setSandboxFlags(SandboxFlags flags)
+    {
+        m_sandboxFlags = flags;
+    }
+
     virtual void dispatchLoad() override;
 
     virtual void trace(Visitor*) override;
+
+private:
+    explicit RemoteBridgeFrameOwner(PassRefPtrWillBeRawPtr<WebLocalFrameImpl>, SandboxFlags);

[dcheng, 2015/02/11 21:57:24]

No need for explicit.

[alexmos, 2015/02/11 22:39:45]

Done.

+
+    RefPtrWillBeMember<WebLocalFrameImpl> m_frame;
+    SandboxFlags m_sandboxFlags;
 };
 
 class WebRemoteFrameImpl final : public RefCountedWillBeGarbageCollectedFinalized<WebRemoteFrameImpl>, public WebRemoteFrame {
@@ -187,7 +211,9 @@ public:
     virtual WebString layerTreeAsText(bool showDebugInfo = false) const override;
 
     virtual WebLocalFrame* createLocalChild(const WebString& name, WebSandboxFlags, WebFrameClient*) override;
+    // FIXME(alexmos): remove once Chrome side is updated to use sandbox flags.
     virtual WebRemoteFrame* createRemoteChild(const WebString& name, WebRemoteFrameClient*) override;
+    virtual WebRemoteFrame* createRemoteChild(const WebString& name, WebSandboxFlags, WebRemoteFrameClient*) override;
 
     void initializeCoreFrame(FrameHost*, FrameOwner*, const AtomicString& name);