Use ConstructFromLiteral instead of implicit conversion

Since we are supposed to end up with an AtomicString, don't rely on implicit conversion, but provide it as static local variable while using ConstructFromLiteral to avoid using strlen.

Review URL: https://codereview.chromium.org/567653002

git-svn-id: svn://svn.chromium.org/blink/trunk@181840 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/svg/SVGUseElement.cpp

@@ -148,14 +148,15 @@ Document* SVGUseElement::externalDocument() const
 
 void transferUseWidthAndHeightIfNeeded(const SVGUseElement& use, SVGElement* shadowElement, const SVGElement& originalElement)
 {
+    DEFINE_STATIC_LOCAL(const AtomicString, hundredPercentString, ("100%", AtomicString::ConstructFromLiteral));
     ASSERT(shadowElement);
     if (isSVGSymbolElement(*shadowElement)) {
         // Spec (<use> on <symbol>): This generated 'svg' will always have explicit values for attributes width and height.
         // If attributes width and/or height are provided on the 'use' element, then these attributes
         // will be transferred to the generated 'svg'. If attributes width and/or height are not specified,
         // the generated 'svg' element will use values of 100% for these attributes.
-        shadowElement->setAttribute(SVGNames::widthAttr, use.width()->isSpecified() ? AtomicString(use.width()->currentValue()->valueAsString()) : "100%");
-        shadowElement->setAttribute(SVGNames::heightAttr, use.height()->isSpecified() ? AtomicString(use.height()->currentValue()->valueAsString()) : "100%");
+        shadowElement->setAttribute(SVGNames::widthAttr, use.width()->isSpecified() ? AtomicString(use.width()->currentValue()->valueAsString()) : hundredPercentString);
+        shadowElement->setAttribute(SVGNames::heightAttr, use.height()->isSpecified() ? AtomicString(use.height()->currentValue()->valueAsString()) : hundredPercentString);
     } else if (isSVGSVGElement(*shadowElement)) {
         // Spec (<use> on <svg>): If attributes width and/or height are provided on the 'use' element, then these
         // values will override the corresponding attributes on the 'svg' in the generated tree.