Attach a WebLayer to a frame element for out-of-process iframes.

Source/web/WebFrameImpl.cpp

Index: Source/web/WebFrameImpl.cpp
diff --git a/Source/web/WebFrameImpl.cpp b/Source/web/WebFrameImpl.cpp
index 23dfa4720749c85b546f9aea1b7b5a338b3e01de..7400be452064b312fa886f5c5695c520b598894f 100644
--- a/Source/web/WebFrameImpl.cpp
+++ b/Source/web/WebFrameImpl.cpp
@@ -188,6 +188,7 @@
 #include "public/platform/WebFileSystem.h"
 #include "public/platform/WebFloatPoint.h"
 #include "public/platform/WebFloatRect.h"
+#include "public/platform/WebLayer.h"
 #include "public/platform/WebPoint.h"
 #include "public/platform/WebRect.h"
 #include "public/platform/WebSize.h"
@@ -555,6 +556,18 @@ WebVector<WebIconURL> WebFrameImpl::iconURLs(int iconTypesMask) const
     return WebVector<WebIconURL>();
 }
 
+void WebFrameImpl::setWebLayer(WebLayer* webLayer)
+{
+    if (frame()) {

[eseidel, 2013/12/11 18:50:01]

early return is generally preferred:
if (!frame()) return;

[kenrb, 2013/12/11 22:44:56]

Done.

+        if (frame()->platformLayer())
+            GraphicsLayer::unregisterContentsLayer(frame()->platformLayer());
+        if (webLayer)
+            GraphicsLayer::registerContentsLayer(webLayer);
+        frame()->setPlatformLayer(webLayer);
+        frame()->ownerElement()->setNeedsStyleRecalc(WebCore::SubtreeStyleChange, WebCore::StyleChangeFromRenderer);

[eseidel, 2013/12/11 18:50:01]

I don't think you want to be scheduling your own style recalc here.  What are
you trying to do?

[kenrb, 2013/12/11 22:44:56]

The goal is to trigger a layout so that the new layer gets picked up and
composited. Is there a better way to do that?

+    }
+}
+
 WebSize WebFrameImpl::scrollOffset() const
 {
     FrameView* view = frameView();