--- a/content/svg/content/src/SVGPathElement.cpp
+++ b/content/svg/content/src/SVGPathElement.cpp
@@ -63,26 +63,20 @@ NS_IMPL_ELEMENT_CLONE_WITH_INIT(SVGPathE
 
 already_AddRefed<SVGAnimatedNumber>
 SVGPathElement::PathLength()
 {
   return mPathLength.ToDOMAnimatedNumber(this);
 }
 
 float
-SVGPathElement::GetTotalLength(ErrorResult& rv)
+SVGPathElement::GetTotalLength()
 {
   RefPtr<Path> flat = GetPathForLengthOrPositionMeasuring();
-
-  if (!flat) {
-    rv.Throw(NS_ERROR_FAILURE);
-    return 0.f;
-  }
-
-  return flat->ComputeLength();
+  return flat ? flat->ComputeLength() : 0.f;
 }
 
 already_AddRefed<nsISVGPoint>
 SVGPathElement::GetPointAtLength(float distance, ErrorResult& rv)
 {
   RefPtr<Path> path = GetPathForLengthOrPositionMeasuring();
   if (!path) {
     rv.Throw(NS_ERROR_FAILURE);
@@ -348,32 +342,33 @@ float
 SVGPathElement::GetPathLengthScale(PathLengthScaleForType aFor)
 {
   NS_ABORT_IF_FALSE(aFor == eForTextPath || aFor == eForStroking,
                     "Unknown enum");
   if (mPathLength.IsExplicitlySet()) {
     float authorsPathLengthEstimate = mPathLength.GetAnimValue();
     if (authorsPathLengthEstimate > 0) {
       RefPtr<Path> path = GetPathForLengthOrPositionMeasuring();
-
+      if (!path) {
+        // The path is empty or invalid so its length must be zero and
+        // we know that 0 / authorsPathLengthEstimate = 0.
+        return 0.0;
+      }
       if (aFor == eForTextPath) {
         // For textPath, a transform on the referenced path affects the
         // textPath layout, so when calculating the actual path length
         // we need to take that into account.
         gfxMatrix matrix = PrependLocalTransformsTo(gfxMatrix());
         if (!matrix.IsIdentity()) {
           RefPtr<PathBuilder> builder =
             path->TransformedCopyToBuilder(ToMatrix(matrix));
           path = builder->Finish();
         }
       }
-
-      if (path) {
-        return path->ComputeLength() / authorsPathLengthEstimate;
-      }
+      return path->ComputeLength() / authorsPathLengthEstimate;
     }
   }
   return 1.0;
 }
 
 TemporaryRef<Path>
 SVGPathElement::BuildPath()
 {

--- a/content/svg/content/src/SVGPathElement.h
+++ b/content/svg/content/src/SVGPathElement.h
@@ -83,17 +83,17 @@ public:
    * Gets the ratio of the actual path length to the content author's estimated
    * length (as provided by the <path> element's 'pathLength' attribute). This
    * is used to scale stroke dashing, and to scale offsets along a textPath.
    */
   float GetPathLengthScale(PathLengthScaleForType aFor);
 
   // WebIDL
   already_AddRefed<SVGAnimatedNumber> PathLength();
-  float GetTotalLength(ErrorResult& rv);
+  float GetTotalLength();
   already_AddRefed<nsISVGPoint> GetPointAtLength(float distance, ErrorResult& rv);
   uint32_t GetPathSegAtLength(float distance);
   already_AddRefed<DOMSVGPathSegClosePath> CreateSVGPathSegClosePath();
   already_AddRefed<DOMSVGPathSegMovetoAbs> CreateSVGPathSegMovetoAbs(float x, float y);
   already_AddRefed<DOMSVGPathSegMovetoRel> CreateSVGPathSegMovetoRel(float x, float y);
   already_AddRefed<DOMSVGPathSegLinetoAbs> CreateSVGPathSegLinetoAbs(float x, float y);
   already_AddRefed<DOMSVGPathSegLinetoRel> CreateSVGPathSegLinetoRel(float x, float y);
   already_AddRefed<DOMSVGPathSegCurvetoCubicAbs>

--- a/content/svg/content/test/test_pathLength.html
+++ b/content/svg/content/test/test_pathLength.html
@@ -27,14 +27,20 @@ https://bugzilla.mozilla.org/show_bug.cg
   is(path.getTotalLength(), 500, "Unexpected path length");
 
   for (var i = 0; i < 2; i++) {
       path.pathSegList.removeItem(path.pathSegList.numberOfItems - 1);
   }
 
   is(path.getTotalLength(), 150, "Unexpected path length");
 
+  while (path.pathSegList.numberOfItems > 0) {
+      path.pathSegList.removeItem(0);
+  }
+
+  is(path.getTotalLength(), 0, "Unexpected path length");
+
   SimpleTest.finish();
 
 </script>
 </pre>
 </body>
 </html>

--- a/dom/webidl/SVGPathElement.webidl
+++ b/dom/webidl/SVGPathElement.webidl
@@ -8,17 +8,16 @@
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 interface SVGPathElement : SVGGraphicsElement {
 
   readonly attribute SVGAnimatedNumber pathLength;
 
-  [Throws]
   float getTotalLength();
   [NewObject, Throws]
   SVGPoint getPointAtLength(float distance);
   unsigned long getPathSegAtLength(float distance);
   [NewObject]
   SVGPathSegClosePath createSVGPathSegClosePath();
   [NewObject]
   SVGPathSegMovetoAbs createSVGPathSegMovetoAbs(float x, float y);