Fix some problems reported by clang static analyzer

Source/core/rendering/RenderMediaControls.cpp

Index: Source/core/rendering/RenderMediaControls.cpp
diff --git a/Source/core/rendering/RenderMediaControls.cpp b/Source/core/rendering/RenderMediaControls.cpp
index 13d1620367a4dd848d1606e5454116b9a6e2e6b3..2115844d4b505bc1c67b787efb3b387f732554c4 100644
--- a/Source/core/rendering/RenderMediaControls.cpp
+++ b/Source/core/rendering/RenderMediaControls.cpp
@@ -156,10 +156,8 @@ static void paintSliderRangeHighlight(const IntRect& rect, const RenderStyle* st
     // Make sure the range width is bigger than border radius at the edges to retain rounded corners.
     if (startOffset < borderRadius && rangeWidth < borderRadius)
         rangeWidth = borderRadius;
-    if (endOffset < borderRadius && rangeWidth < borderRadius) {
-        startPosition -= borderRadius - rangeWidth;
+    if (endOffset < borderRadius && rangeWidth < borderRadius)
         rangeWidth = borderRadius;
-    }
 
     // Set rectangle to highlight range.
     IntRect highlightRect = rect;