Use isHTMLTextAreaElement and toHTMLTextAreaElement

Source/core/rendering/RenderTextControlMultiLine.cpp

Index: Source/core/rendering/RenderTextControlMultiLine.cpp
diff --git a/Source/core/rendering/RenderTextControlMultiLine.cpp b/Source/core/rendering/RenderTextControlMultiLine.cpp
index 6da489fbf750b4d9f4ac5f2d36a6bac0dec0d496..8a8887d7651da5031e815ba6c147028981365c91 100644
--- a/Source/core/rendering/RenderTextControlMultiLine.cpp
+++ b/Source/core/rendering/RenderTextControlMultiLine.cpp
@@ -36,7 +36,7 @@ RenderTextControlMultiLine::RenderTextControlMultiLine(HTMLTextAreaElement* elem
 RenderTextControlMultiLine::~RenderTextControlMultiLine()
 {
     if (node() && node()->inDocument())
-        static_cast<HTMLTextAreaElement*>(node())->rendererWillBeDestroyed();
+        toHTMLTextAreaElement(node())->rendererWillBeDestroyed();
 }
 
 bool RenderTextControlMultiLine::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction hitTestAction)
@@ -63,13 +63,13 @@ float RenderTextControlMultiLine::getAvgCharWidth(AtomicString family)
 
 LayoutUnit RenderTextControlMultiLine::preferredContentLogicalWidth(float charWidth) const
 {
-    int factor = static_cast<HTMLTextAreaElement*>(node())->cols();
+    int factor = toHTMLTextAreaElement(node())->cols();
     return static_cast<LayoutUnit>(ceilf(charWidth * factor)) + scrollbarThickness();
 }
 
 LayoutUnit RenderTextControlMultiLine::computeControlLogicalHeight(LayoutUnit lineHeight, LayoutUnit nonContentHeight) const
 {
-    return lineHeight * static_cast<HTMLTextAreaElement*>(node())->rows() + nonContentHeight;
+    return lineHeight * toHTMLTextAreaElement(node())->rows() + nonContentHeight;
 }
 
 int RenderTextControlMultiLine::baselinePosition(FontBaseline baselineType, bool firstLine, LineDirectionMode direction, LinePositionMode linePositionMode) const