Recalc styles on resize if we have viewport units.

Source/WebCore/css/CSSGrammar.y.in

Index: Source/WebCore/css/CSSGrammar.y.in
diff --git a/Source/WebCore/css/CSSGrammar.y.in b/Source/WebCore/css/CSSGrammar.y.in
index 32b439831bb4eea5e203e83a85d9cc873d897eb3..003c1a81817c9c9e8f06b37e91748b2b1d6006ab 100644
--- a/Source/WebCore/css/CSSGrammar.y.in
+++ b/Source/WebCore/css/CSSGrammar.y.in
@@ -1795,10 +1795,26 @@ unary_term:
           parser->m_styleSheet->parserSetUsesRemUnits(true);
   }
   | CHS maybe_space { $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_CHS; }
-  | VW maybe_space { $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_VW; }
-  | VH maybe_space { $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_VH; }
-  | VMIN maybe_space { $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_VMIN; }
-  | VMAX maybe_space { $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_VMAX; }
+  | VW maybe_space {
+      $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_VW;
+      if (parser->m_styleSheet)
+          parser->m_styleSheet->parserSetUsesViewportUnits(true);
+  }
+  | VH maybe_space {
+      $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_VH;
+      if (parser->m_styleSheet)
+          parser->m_styleSheet->parserSetUsesViewportUnits(true);
+  }
+  | VMIN maybe_space {
+      $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_VMIN;
+      if (parser->m_styleSheet)
+          parser->m_styleSheet->parserSetUsesViewportUnits(true);
+  }
+  | VMAX maybe_space {
+      $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_VMAX;
+      if (parser->m_styleSheet)
+          parser->m_styleSheet->parserSetUsesViewportUnits(true);
+  }
   | DPPX maybe_space { $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_DPPX; }
   | DPI maybe_space { $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_DPI; }
   | DPCM maybe_space { $$.id = 0; $$.fValue = $1; $$.unit = CSSPrimitiveValue::CSS_DPCM; }