Move Document.fullscreenElement to DocumentOrShadowRoot

third_party/WebKit/Source/core/dom/DocumentOrShadowRoot.h

Index: third_party/WebKit/Source/core/dom/DocumentOrShadowRoot.h
diff --git a/third_party/WebKit/Source/core/dom/DocumentOrShadowRoot.h b/third_party/WebKit/Source/core/dom/DocumentOrShadowRoot.h
index f3ff270b36ce7161ed35f1d6b5320a6b6704d8ff..166cf1153250af122975e3e0f9a80ddc9bfc8f50 100644
--- a/third_party/WebKit/Source/core/dom/DocumentOrShadowRoot.h
+++ b/third_party/WebKit/Source/core/dom/DocumentOrShadowRoot.h
@@ -6,6 +6,7 @@
 #define DocumentOrShadowRoot_h
 
 #include "core/dom/Document.h"
+#include "core/dom/Fullscreen.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/frame/UseCounter.h"
 
@@ -76,6 +77,60 @@ public:
             return nullptr;
         return shadowRoot.adjustedElement(*target);
     }
+
+    static Element* currentFullScreenElement(Document& document)
+    {
+        Element* element = Fullscreen::currentFullScreenElementFrom(document);
+        if (!element)
+            return nullptr;
+
+        // For Shadow DOM V0 compatibility: We allow returning an element in V0 shadow tree,
+        // even though it leaks the Shadow DOM.
+        // TODO(kochi): Once V0 code is removed, the following V0 check is unnecessary.
+        if (element->isInV0ShadowTree()) {
+            UseCounter::count(document, UseCounter::DocumentFullscreenElementInV0Shadow);
+            return element;
+        }
+        return document.adjustedElement(*element);
+    }
+
+    static Element* currentFullScreenElement(ShadowRoot& shadowRoot)
+    {
+        // TODO(kochi): Once V0 code is removed, the following non-V1 check is unnecessary.
+        // After V0 code is removed, we can use the same logic for Document and ShadowRoot.
+        if (!shadowRoot.isV1())
+            return nullptr;
+
+        Element* element = Fullscreen::currentFullScreenElementFrom(shadowRoot.document());
+        return element ? shadowRoot.adjustedElement(*element) : nullptr;
+    }
+
+    static Element* fullscreenElement(Document& document)
+    {
+        Element* element = Fullscreen::fullscreenElementFrom(document);
+        if (!element)
+            return nullptr;
+
+        // For Shadow DOM V0 compatibility: We allow returning an element in V0 shadow tree,
+        // even though it leaks the Shadow DOM.
+        // TODO(kochi): Once V0 code is removed, the following V0 check is unnecessary.
+        if (element->isInV0ShadowTree()) {
+            UseCounter::count(document, UseCounter::DocumentFullscreenElementInV0Shadow);
+            return element;
+        }
+        return document.adjustedElement(*element);
+    }
+
+    static Element* fullscreenElement(ShadowRoot& shadowRoot)
+    {
+        // TODO(kochi): Once V0 code is removed, the following non-V1 check is unnecessary.
+        // After V0 code is removed, we can use the same logic for Document and ShadowRoot.
+        if (!shadowRoot.isV1())
+            return nullptr;
+
+        Element* element = Fullscreen::fullscreenElementFrom(shadowRoot.document());
+        return element ? shadowRoot.adjustedElement(*element) : nullptr;
+    }
 };
 
 } // namespace blink