Use tighter typing in editing: PlainTextRange / ReplaceNodeWithSpanCommand

Source/core/editing/ReplaceNodeWithSpanCommand.h

Index: Source/core/editing/ReplaceNodeWithSpanCommand.h
diff --git a/Source/core/editing/ReplaceNodeWithSpanCommand.h b/Source/core/editing/ReplaceNodeWithSpanCommand.h
index 1a5d00f8710a71757032904d9b02d14aa587000c..24c4bd2ea14429df37a06764e2f0ff3290cc84fc 100644
--- a/Source/core/editing/ReplaceNodeWithSpanCommand.h
+++ b/Source/core/editing/ReplaceNodeWithSpanCommand.h
@@ -36,6 +36,7 @@
 namespace blink {
 
 class HTMLElement;
+class HTMLSpanElement;
 
 // More accurately, this is ReplaceElementWithSpanPreservingChildrenAndAttributesCommand
 class ReplaceNodeWithSpanCommand FINAL : public SimpleEditCommand {
@@ -45,7 +46,7 @@ public:
         return adoptRefWillBeNoop(new ReplaceNodeWithSpanCommand(element));
     }
 
-    HTMLElement* spanElement() { return m_spanElement.get(); }
+    HTMLSpanElement* spanElement() { return m_spanElement.get(); }
 
     virtual void trace(Visitor*) OVERRIDE;
 
@@ -56,7 +57,7 @@ private:
     virtual void doUnapply() OVERRIDE;
 
     RefPtrWillBeMember<HTMLElement> m_elementToReplace;
-    RefPtrWillBeMember<HTMLElement> m_spanElement;
+    RefPtrWillBeMember<HTMLSpanElement> m_spanElement;
 };
 
 } // namespace blink