SVG doesn't recognize rem units

Source/core/svg/SVGLengthContext.cpp

Index: Source/core/svg/SVGLengthContext.cpp
diff --git a/Source/core/svg/SVGLengthContext.cpp b/Source/core/svg/SVGLengthContext.cpp
index f9cc9e6e5f310e01e1801dfa7ec833d84b7a4e76..dda2635eee1712e20a160372ed55d446d46f633c 100644
--- a/Source/core/svg/SVGLengthContext.cpp
+++ b/Source/core/svg/SVGLengthContext.cpp
@@ -25,6 +25,7 @@
 
 #include "core/css/CSSHelper.h"
 #include "core/css/CSSPrimitiveValue.h"
+#include "core/dom/NodeLayoutStyle.h"
 #include "core/layout/LayoutObject.h"
 #include "core/layout/style/LayoutStyle.h"
 #include "core/svg/SVGSVGElement.h"
@@ -168,6 +169,9 @@ float SVGLengthContext::convertValueToUserUnits(float value, SVGLengthMode mode,
     case LengthTypePC:
         userUnits = value * cssPixelsPerPica;
         break;
+    case LengthTypeREMS:
+        userUnits = convertValueFromREMSToUserUnits(value);
+        break;
     default:
         ASSERT_NOT_REACHED();
         break;
@@ -198,6 +202,8 @@ float SVGLengthContext::convertValueFromUserUnits(float value, SVGLengthMode mod
         return convertValueFromUserUnitsToEMS(value);
     case LengthTypeEXS:
         return convertValueFromUserUnitsToEXS(value);
+    case LengthTypeREMS:
+        return convertValueFromUserUnitsToREMS(value);
     case LengthTypePX:
         return value;
     case LengthTypeCM:
@@ -254,6 +260,63 @@ float SVGLengthContext::convertValueFromEMSToUserUnits(float value) const
     return value * style->specifiedFontSize();
 }
 
+float SVGLengthContext::convertValueFromUserUnitsToREMS(float value) const
+{
+    if (!m_context)
+        return 0;
+
+    const LayoutStyle* style = 0;
+    const ContainerNode* currentContext = m_context;
+
+    do {
+        if (currentContext->layoutObject()) {

[Erik Dahlström (inactive), 2015/04/02 07:58:41]

Do we really need this loop? Why not just fetch the document directly from
m_context->document()?

The same applies to the method below as well.

[Shanmuga Pandi, 2015/04/02 13:06:51]

Done.

+            const Document& document = currentContext->layoutObject()->document();
+            Node* documentElement = document.documentElement();
+            const LayoutStyle* documentStyle = document.layoutStyle();
+            style = documentElement && !currentContext->layoutObject()->isDocumentElement() ? documentElement->layoutStyle() : documentStyle;
+            if (!style)
+                style = documentStyle;
+            break;
+        }
+        currentContext = currentContext->parentNode();
+    } while (currentContext);
+
+    if (!style)
+        return 0;
+
+    float fontSize = style->specifiedFontSize();
+    if (!fontSize)
+        return 0;
+
+    return value / fontSize;
+}
+
+float SVGLengthContext::convertValueFromREMSToUserUnits(float value) const
+{
+    if (!m_context)
+        return 0;
+
+    const LayoutStyle* style = 0;
+    const ContainerNode* currentContext = m_context;
+
+    do {
+        if (currentContext->layoutObject()) {
+            const Document& document = currentContext->layoutObject()->document();
+            Node* documentElement = document.documentElement();
+            const LayoutStyle* documentStyle = document.layoutStyle();
+            style = documentElement && !currentContext->layoutObject()->isDocumentElement() ? documentElement->layoutStyle() : documentStyle;
+            if (!style)
+                style = documentStyle;
+            break;
+        }
+        currentContext = currentContext->parentNode();
+    } while (currentContext);
+
+    if (!style)
+        return 0;
+    return value * style->specifiedFontSize();
+}
+
 float SVGLengthContext::convertValueFromUserUnitsToEXS(float value) const
 {
     const LayoutStyle* style = layoutStyleForLengthResolving(m_context);