diff --git a/content/svg/content/src/DOMSVGPathSeg.cpp b/content/svg/content/src/DOMSVGPathSeg.cpp
index d139e29e24d6..c0f785fff65d 100644
--- a/content/svg/content/src/DOMSVGPathSeg.cpp
+++ b/content/svg/content/src/DOMSVGPathSeg.cpp
@@ -180,7 +180,6 @@ DOMSVGPathSeg::IndexIsValid()
       }                                                                       \
       AutoChangePathSegNotifier notifier(this);                               \
       InternalItem()[1+index] = float(a##propName);                           \
-      InvalidateCachedList();                                                 \
     } else {                                                                  \
       mArgs[index] = float(a##propName);                                      \
     }                                                                         \
diff --git a/content/svg/content/src/DOMSVGPathSeg.h b/content/svg/content/src/DOMSVGPathSeg.h
index ac1986a97098..388356af8031 100644
--- a/content/svg/content/src/DOMSVGPathSeg.h
+++ b/content/svg/content/src/DOMSVGPathSeg.h
@@ -209,10 +209,6 @@ protected:
    */
   float* InternalItem();
 
-  void InvalidateCachedList() {
-    mList->InternalList().mCachedPath = nullptr;
-  }
-
   virtual float* PtrToMemberArgs() = 0;
 
 #ifdef DEBUG
diff --git a/content/svg/content/src/DOMSVGPathSegList.cpp b/content/svg/content/src/DOMSVGPathSegList.cpp
index 63177e7626e4..b639c951506a 100644
--- a/content/svg/content/src/DOMSVGPathSegList.cpp
+++ b/content/svg/content/src/DOMSVGPathSegList.cpp
@@ -383,7 +383,6 @@ DOMSVGPathSegList::InsertItemBefore(DOMSVGPathSeg& aNewItem,
   domItem->ToSVGPathSegEncodedData(segAsRaw);
 
   InternalList().mData.InsertElementsAt(internalIndex, segAsRaw, 1 + argCount);
-  InternalList().mCachedPath = nullptr;
   mItems.InsertElementAt(aIndex, ItemProxy(domItem.get(), internalIndex));
 
   // This MUST come after the insertion into InternalList(), or else under the
@@ -440,7 +439,6 @@ DOMSVGPathSegList::ReplaceItem(DOMSVGPathSeg& aNewItem,
   bool ok = !!InternalList().mData.ReplaceElementsAt(
                   internalIndex, 1 + oldArgCount,
                   segAsRaw, 1 + newArgCount);
-  InternalList().mCachedPath = nullptr;
   if (!ok) {
     aError.Throw(NS_ERROR_OUT_OF_MEMORY);
     return nullptr;
@@ -495,7 +493,6 @@ DOMSVGPathSegList::RemoveItem(uint32_t aIndex,
   MaybeRemoveItemFromAnimValListAt(aIndex, argCount);
 
   InternalList().mData.RemoveElementsAt(internalIndex, 1 + argCount);
-  InternalList().mCachedPath = nullptr;
   mItems.RemoveElementAt(aIndex);
 
   UpdateListIndicesFromIndex(aIndex, -(argCount + 1));
diff --git a/content/svg/content/src/SVGMotionSMILAnimationFunction.cpp b/content/svg/content/src/SVGMotionSMILAnimationFunction.cpp
index 0d05e7930783..abe6b16b493e 100644
--- a/content/svg/content/src/SVGMotionSMILAnimationFunction.cpp
+++ b/content/svg/content/src/SVGMotionSMILAnimationFunction.cpp
@@ -227,7 +227,7 @@ SVGMotionSMILAnimationFunction::
       bool ok =
         path.GetDistancesFromOriginToEndsOfVisibleSegments(&mPathVertices);
       if (ok && mPathVertices.Length()) {
-        mPath = pathElem->GetPathForLengthOrPositionMeasuring();
+        mPath = pathElem->GetOrBuildPathForMeasuring();
       }
     }
   }
@@ -252,7 +252,7 @@ SVGMotionSMILAnimationFunction::RebuildPathAndVerticesFromPathAttr()
     return;
   }
 
-  mPath = path.ToPathForLengthOrPositionMeasuring();
+  mPath = path.BuildPathForMeasuring();
   bool ok = path.GetDistancesFromOriginToEndsOfVisibleSegments(&mPathVertices);
   if (!ok || !mPathVertices.Length()) {
     mPath = nullptr;
diff --git a/content/svg/content/src/SVGPathData.cpp b/content/svg/content/src/SVGPathData.cpp
index facf77df8a0d..87c228d22b44 100644
--- a/content/svg/content/src/SVGPathData.cpp
+++ b/content/svg/content/src/SVGPathData.cpp
@@ -37,7 +37,6 @@ SVGPathData::CopyFrom(const SVGPathData& rhs)
     // Yes, we do want fallible alloc here
     return NS_ERROR_OUT_OF_MEMORY;
   }
-  mCachedPath = nullptr;
   mData = rhs.mData;
   return NS_OK;
 }
@@ -72,7 +71,6 @@ SVGPathData::SetValueFromString(const nsAString& aValue)
   // the first error. We still return any error though so that callers know if
   // there's a problem.
 
-  mCachedPath = nullptr;
   nsSVGPathDataParser pathParser(aValue, this);
   return pathParser.Parse() ? NS_OK : NS_ERROR_DOM_SYNTAX_ERR;
 }
@@ -85,7 +83,6 @@ SVGPathData::AppendSeg(uint32_t aType, ...)
   if (!mData.SetLength(newLength)) {
     return NS_ERROR_OUT_OF_MEMORY;
   }
-  mCachedPath = nullptr;
 
   mData[oldLength] = SVGPathSegUtils::EncodeType(aType);
   va_list args;
@@ -510,7 +507,7 @@ SVGPathData::BuildPath(PathBuilder* builder,
 }
 
 TemporaryRef<Path>
-SVGPathData::ToPathForLengthOrPositionMeasuring() const
+SVGPathData::BuildPathForMeasuring() const
 {
   // Since the path that we return will not be used for painting it doesn't
   // matter what we pass to CreatePathBuilder as aFillRule. Hawever, we do want
@@ -520,15 +517,11 @@ SVGPathData::ToPathForLengthOrPositionMeasuring() const
   // pass as aStrokeWidth doesn't matter (since it's only used to determine the
   // length of those extra little lines).
 
-  if (!mCachedPath) {
-    RefPtr<DrawTarget> drawTarget =
-      gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget();
-    RefPtr<PathBuilder> builder =
-      drawTarget->CreatePathBuilder(FillRule::FILL_WINDING);
-    mCachedPath = BuildPath(builder, NS_STYLE_STROKE_LINECAP_BUTT, 0);
-  }
-
-  return mCachedPath;
+  RefPtr<DrawTarget> drawTarget =
+    gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget();
+  RefPtr<PathBuilder> builder =
+    drawTarget->CreatePathBuilder(FillRule::FILL_WINDING);
+  return BuildPath(builder, NS_STYLE_STROKE_LINECAP_BUTT, 0);
 }
 
 static double
diff --git a/content/svg/content/src/SVGPathData.h b/content/svg/content/src/SVGPathData.h
index 4c1c4a2dfea1..3fd26b6bc07d 100644
--- a/content/svg/content/src/SVGPathData.h
+++ b/content/svg/content/src/SVGPathData.h
@@ -163,7 +163,7 @@ public:
    * ApproximateZeroLengthSubpathSquareCaps can insert if we have square-caps.
    * See the comment for that function for more info on that.
    */
-  TemporaryRef<Path> ToPathForLengthOrPositionMeasuring() const;
+  TemporaryRef<Path> BuildPathForMeasuring() const;
 
   TemporaryRef<Path> BuildPath(PathBuilder* aBuilder,
                                uint8_t aCapStyle,
@@ -193,7 +193,6 @@ protected:
   nsresult CopyFrom(const SVGPathData& rhs);
 
   float& operator[](uint32_t aIndex) {
-    mCachedPath = nullptr;
     return mData[aIndex];
   }
 
@@ -202,14 +201,12 @@ protected:
    * increased, in which case the list will be left unmodified.
    */
   bool SetLength(uint32_t aLength) {
-    mCachedPath = nullptr;
     return mData.SetLength(aLength);
   }
 
   nsresult SetValueFromString(const nsAString& aValue);
 
   void Clear() {
-    mCachedPath = nullptr;
     mData.Clear();
   }
 
@@ -223,11 +220,10 @@ protected:
 
   nsresult AppendSeg(uint32_t aType, ...); // variable number of float args
 
-  iterator begin() { mCachedPath = nullptr; return mData.Elements(); }
-  iterator end() { mCachedPath = nullptr; return mData.Elements() + mData.Length(); }
+  iterator begin() { return mData.Elements(); }
+  iterator end() { return mData.Elements() + mData.Length(); }
 
   FallibleTArray<float> mData;
-  mutable RefPtr<gfx::Path> mCachedPath;
 };
 
 
diff --git a/content/svg/content/src/SVGPathElement.cpp b/content/svg/content/src/SVGPathElement.cpp
index 786754fb8fa4..25bc7e825250 100644
--- a/content/svg/content/src/SVGPathElement.cpp
+++ b/content/svg/content/src/SVGPathElement.cpp
@@ -70,14 +70,14 @@ SVGPathElement::PathLength()
 float
 SVGPathElement::GetTotalLength()
 {
-  RefPtr<Path> flat = GetPathForLengthOrPositionMeasuring();
+  RefPtr<Path> flat = GetOrBuildPathForMeasuring();
   return flat ? flat->ComputeLength() : 0.f;
 }
 
 already_AddRefed<nsISVGPoint>
 SVGPathElement::GetPointAtLength(float distance, ErrorResult& rv)
 {
-  RefPtr<Path> path = GetPathForLengthOrPositionMeasuring();
+  RefPtr<Path> path = GetOrBuildPathForMeasuring();
   if (!path) {
     rv.Throw(NS_ERROR_FAILURE);
     return nullptr;
@@ -305,9 +305,9 @@ SVGPathElement::IsAttributeMapped(const nsIAtom* name) const
 }
 
 TemporaryRef<Path>
-SVGPathElement::GetPathForLengthOrPositionMeasuring()
+SVGPathElement::GetOrBuildPathForMeasuring()
 {
-  return mD.GetAnimValue().ToPathForLengthOrPositionMeasuring();
+  return mD.GetAnimValue().BuildPathForMeasuring();
 }
 
 //----------------------------------------------------------------------
@@ -340,7 +340,7 @@ SVGPathElement::GetPathLengthScale(PathLengthScaleForType aFor)
   if (mPathLength.IsExplicitlySet()) {
     float authorsPathLengthEstimate = mPathLength.GetAnimValue();
     if (authorsPathLengthEstimate > 0) {
-      RefPtr<Path> path = GetPathForLengthOrPositionMeasuring();
+      RefPtr<Path> path = GetOrBuildPathForMeasuring();
       if (!path) {
         // The path is empty or invalid so its length must be zero and
         // we know that 0 / authorsPathLengthEstimate = 0.
diff --git a/content/svg/content/src/SVGPathElement.h b/content/svg/content/src/SVGPathElement.h
index 8bbf8cca8c7a..10e49a1f4dfb 100644
--- a/content/svg/content/src/SVGPathElement.h
+++ b/content/svg/content/src/SVGPathElement.h
@@ -57,8 +57,7 @@ public:
    * ApproximateZeroLengthSubpathSquareCaps can insert if we have square-caps.
    * See the comment for that function for more info on that.
    */
-  virtual TemporaryRef<Path>
-    GetPathForLengthOrPositionMeasuring() MOZ_OVERRIDE;
+  virtual TemporaryRef<Path> GetOrBuildPathForMeasuring() MOZ_OVERRIDE;
 
   // nsIContent interface
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult) const MOZ_OVERRIDE;
diff --git a/content/svg/content/src/nsSVGElement.cpp b/content/svg/content/src/nsSVGElement.cpp
index 977be816c739..df0e5be5c0d1 100644
--- a/content/svg/content/src/nsSVGElement.cpp
+++ b/content/svg/content/src/nsSVGElement.cpp
@@ -15,6 +15,7 @@
 #include "nsICSSDeclaration.h"
 #include "nsIDocument.h"
 #include "nsIDOMMutationEvent.h"
+#include "nsSVGPathGeometryElement.h"
 #include "mozilla/InternalMutationEvent.h"
 #include "nsError.h"
 #include "nsIPresShell.h"
@@ -1605,6 +1606,8 @@ nsSVGElement::DidChangeLength(uint8_t aAttrEnum,
 void
 nsSVGElement::DidAnimateLength(uint8_t aAttrEnum)
 {
+  ClearAnyCachedPath();
+
   nsIFrame* frame = GetPrimaryFrame();
 
   if (frame) {
@@ -1850,6 +1853,8 @@ nsSVGElement::DidAnimatePointList()
   NS_ABORT_IF_FALSE(GetPointListAttrName(),
                     "Animating non-existent path data?");
 
+  ClearAnyCachedPath();
+
   nsIFrame* frame = GetPrimaryFrame();
 
   if (frame) {
@@ -1885,6 +1890,8 @@ nsSVGElement::DidAnimatePathSegList()
   NS_ABORT_IF_FALSE(GetPathDataAttrName(),
                     "Animating non-existent path data?");
 
+  ClearAnyCachedPath();
+
   nsIFrame* frame = GetPrimaryFrame();
 
   if (frame) {
diff --git a/content/svg/content/src/nsSVGElement.h b/content/svg/content/src/nsSVGElement.h
index 9745325dbf66..d8794e2e4cbc 100644
--- a/content/svg/content/src/nsSVGElement.h
+++ b/content/svg/content/src/nsSVGElement.h
@@ -33,6 +33,7 @@ class nsSVGIntegerPair;
 class nsSVGLength2;
 class nsSVGNumber2;
 class nsSVGNumberPair;
+class nsSVGPathGeometryElement;
 class nsSVGString;
 class nsSVGViewBox;
 
@@ -313,6 +314,7 @@ public:
     return mClassAnimAttr;
   }
 
+  virtual void ClearAnyCachedPath() {}
   virtual nsIDOMNode* AsDOMNode() MOZ_FINAL MOZ_OVERRIDE { return this; }
   virtual bool IsTransformable() { return false; }
 
diff --git a/content/svg/content/src/nsSVGPathGeometryElement.cpp b/content/svg/content/src/nsSVGPathGeometryElement.cpp
index 01669fec1ae9..37c8c648874e 100644
--- a/content/svg/content/src/nsSVGPathGeometryElement.cpp
+++ b/content/svg/content/src/nsSVGPathGeometryElement.cpp
@@ -8,6 +8,7 @@
 #include "gfxPlatform.h"
 #include "mozilla/gfx/2D.h"
 #include "nsComputedDOMStyle.h"
+#include "nsSVGUtils.h"
 #include "nsSVGLength2.h"
 #include "SVGContentUtils.h"
 
@@ -22,6 +23,19 @@ nsSVGPathGeometryElement::nsSVGPathGeometryElement(already_AddRefed<mozilla::dom
 {
 }
 
+nsresult
+nsSVGPathGeometryElement::AfterSetAttr(int32_t aNamespaceID, nsIAtom* aName,
+                                       const nsAttrValue* aValue, bool aNotify)
+{
+  if (mCachedPath &&
+      aNamespaceID == kNameSpaceID_None &&
+      AttributeDefinesGeometry(aName)) {
+    mCachedPath = nullptr;
+  }
+  return nsSVGPathGeometryElementBase::AfterSetAttr(aNamespaceID, aName,
+                                                    aValue, aNotify);
+}
+
 bool
 nsSVGPathGeometryElement::AttributeDefinesGeometry(const nsIAtom *aName)
 {
@@ -61,7 +75,30 @@ nsSVGPathGeometryElement::GetMarkPoints(nsTArray<nsSVGMark> *aMarks)
 }
 
 TemporaryRef<Path>
-nsSVGPathGeometryElement::GetPathForLengthOrPositionMeasuring()
+nsSVGPathGeometryElement::GetOrBuildPath(const DrawTarget& aDrawTarget,
+                                         FillRule aFillRule)
+{
+  // We only cache the path if it matches the backend used for screen painting:
+  bool cacheable  = aDrawTarget.GetBackendType() ==
+                      gfxPlatform::GetPlatform()->GetContentBackend();
+
+  // Checking for and returning mCachedPath before checking the pref means
+  // that the pref is only live on page reload (or app restart for SVG in
+  // chrome). The benefit is that we avoid causing a CPU memory cache miss by
+  // looking at the global variable that the pref's stored in.
+  if (cacheable && mCachedPath) {
+    return mCachedPath;
+  }
+  RefPtr<PathBuilder> builder = aDrawTarget.CreatePathBuilder(aFillRule);
+  RefPtr<Path> path = BuildPath(builder);
+  if (cacheable && NS_SVGPathCachingEnabled()) {
+    mCachedPath = path;
+  }
+  return path.forget();
+}
+
+TemporaryRef<Path>
+nsSVGPathGeometryElement::GetOrBuildPathForMeasuring()
 {
   return nullptr;
 }
diff --git a/content/svg/content/src/nsSVGPathGeometryElement.h b/content/svg/content/src/nsSVGPathGeometryElement.h
index 7b24e9bdc01f..7c9603be7e82 100644
--- a/content/svg/content/src/nsSVGPathGeometryElement.h
+++ b/content/svg/content/src/nsSVGPathGeometryElement.h
@@ -31,6 +31,7 @@ typedef mozilla::dom::SVGGraphicsElement nsSVGPathGeometryElementBase;
 class nsSVGPathGeometryElement : public nsSVGPathGeometryElementBase
 {
 protected:
+  typedef mozilla::gfx::DrawTarget DrawTarget;
   typedef mozilla::gfx::FillRule FillRule;
   typedef mozilla::gfx::Float Float;
   typedef mozilla::gfx::Path Path;
@@ -39,6 +40,17 @@ protected:
 public:
   explicit nsSVGPathGeometryElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
+  virtual nsresult AfterSetAttr(int32_t aNamespaceID, nsIAtom* aName,
+                                const nsAttrValue* aValue, bool aNotify) MOZ_OVERRIDE;
+
+  /**
+   * Causes this element to discard any Path object that GetOrBuildPath may
+   * have cached.
+   */
+  virtual void ClearAnyCachedPath() MOZ_OVERRIDE MOZ_FINAL {
+    mCachedPath = nullptr;
+  }
+
   virtual bool AttributeDefinesGeometry(const nsIAtom *aName);
 
   /**
@@ -57,17 +69,44 @@ public:
 
   /**
    * Returns a Path that can be used to paint, hit-test or calculate bounds for
+   * this element. May return nullptr if there is no [valid] path. The path
+   * that is created may be cached and returned on subsequent calls.
+   */
+  virtual mozilla::TemporaryRef<Path> GetOrBuildPath(const DrawTarget& aDrawTarget,
+                                                     FillRule fillRule);
+
+  /**
+   * The same as GetOrBuildPath, but bypasses the cache (neither returns any
+   * previously cached Path, nor caches the Path that in does return).
    * this element. May return nullptr if there is no [valid] path.
    */
-  virtual mozilla::TemporaryRef<Path> BuildPath(PathBuilder* aBuilder = nullptr) = 0;
+  virtual mozilla::TemporaryRef<Path> BuildPath(PathBuilder* aBuilder) = 0;
 
-  virtual mozilla::TemporaryRef<Path> GetPathForLengthOrPositionMeasuring();
+  /**
+   * Returns a Path that can be used to measure the length of this elements
+   * path, or to find the position at a given distance along it.
+   *
+   * This is currently equivalent to calling GetOrBuildPath, but it may not be
+   * in the future. The reason for this function to be separate from
+   * GetOrBuildPath is because SVGPathData::BuildPath inserts small lines into
+   * the path if zero length subpaths are encountered, in order to implement
+   * the SVG specifications requirements that zero length subpaths should
+   * render circles/squares if stroke-linecap is round/square, respectively.
+   * In principle these inserted lines could interfere with path measurement,
+   * so we keep callers that are looking to do measurement separate in case we
+   * run into problems with the inserted lines negatively affecting measuring
+   * for content.
+   */
+  virtual mozilla::TemporaryRef<Path> GetOrBuildPathForMeasuring();
 
   /**
    * Returns the current computed value of the CSS property 'fill-rule' for
    * this element.
    */
   FillRule GetFillRule();
+
+protected:
+  mutable mozilla::RefPtr<Path> mCachedPath;
 };
 
 #endif
diff --git a/layout/reftests/svg/dynamic-fill-rule-01-ref.svg b/layout/reftests/svg/dynamic-fill-rule-01-ref.svg
new file mode 100644
index 000000000000..a31a09a7cbe2
--- /dev/null
+++ b/layout/reftests/svg/dynamic-fill-rule-01-ref.svg
@@ -0,0 +1,20 @@
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<svg version="1.1" xmlns="http://www.w3.org/2000/svg">
+  <title>Reference for dynamic changes to fill-rule</title>
+  <!-- From https://bugzilla.mozilla.org/show_bug.cgi?id=932762 -->
+
+  <!-- for p1 -->
+  <rect x="50" y="100" width="150" height="50"/>
+  <rect x="100" y="50" width="50" height="150"/>
+
+  <!-- for p2 -->
+  <rect x="250" y="100" width="50" height="50"/>
+  <rect x="350" y="100" width="50" height="50"/>
+  <rect x="300" y="50" width="50" height="50"/>
+  <rect x="300" y="150" width="50" height="50"/>
+
+</svg>
+
diff --git a/layout/reftests/svg/dynamic-fill-rule-01.svg b/layout/reftests/svg/dynamic-fill-rule-01.svg
new file mode 100644
index 000000000000..9fb12f4ae0fa
--- /dev/null
+++ b/layout/reftests/svg/dynamic-fill-rule-01.svg
@@ -0,0 +1,25 @@
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<svg version="1.1" xmlns="http://www.w3.org/2000/svg" class="reftest-wait">
+  <title>Testcase for dynamic changes to fill-rule</title>
+  <!-- From https://bugzilla.mozilla.org/show_bug.cgi?id=932762 -->
+  <script>
+
+function doTest() {
+  document.getElementById("p1").removeAttribute("style");
+  document.getElementById("p2").setAttribute("style", "fill-rule: evenodd;");
+  document.documentElement.removeAttribute("class");
+}
+
+window.addEventListener("MozReftestInvalidate", doTest, false);
+window.setTimeout(doTest, 4000); // fallback for running outside reftest
+
+  </script>
+  <path id="p1" style="fill-rule: evenodd;"
+        d="M100,50 l0,150 50,0 0,-100 -100,0 0,50 150,0 0,-50 -50,0 0,-50 z"/>
+  <path id="p2"
+        d="M300,50 l0,150 50,0 0,-100 -100,0 0,50 150,0 0,-50 -50,0 0,-50 z"/>
+</svg>
+
diff --git a/layout/reftests/svg/reftest.list b/layout/reftests/svg/reftest.list
index 09ea02eafc4c..b3e62a31c829 100644
--- a/layout/reftests/svg/reftest.list
+++ b/layout/reftests/svg/reftest.list
@@ -78,6 +78,7 @@ fuzzy-if(Android,4,87) == dynamic-clipPath-01.svg pass.svg
 == dynamic-feFlood-01.svg pass.svg
 asserts(0-1) == dynamic-feImage-01.svg pass.svg # intermittent assertions (bug 886080)
 == dynamic-fill-01.svg dynamic-fill-01-ref.svg
+== dynamic-fill-rule-01.svg dynamic-fill-rule-01-ref.svg
 fuzzy-if(d2d,1,10000) == dynamic-filter-contents-01a.svg dynamic-filter-contents-01-ref.svg
 fuzzy-if(d2d,1,10000) == dynamic-filter-contents-01b.svg dynamic-filter-contents-01-ref.svg
 == dynamic-gradient-contents-01.svg pass.svg
diff --git a/layout/svg/SVGTextFrame.cpp b/layout/svg/SVGTextFrame.cpp
index 45c6b743920c..f52d123381fc 100644
--- a/layout/svg/SVGTextFrame.cpp
+++ b/layout/svg/SVGTextFrame.cpp
@@ -4805,7 +4805,7 @@ SVGTextFrame::GetTextPath(nsIFrame* aTextPathFrame)
   nsSVGPathGeometryElement *element =
     static_cast<nsSVGPathGeometryElement*>(pathFrame->GetContent());
 
-  RefPtr<Path> path = element->GetPathForLengthOrPositionMeasuring();
+  RefPtr<Path> path = element->GetOrBuildPathForMeasuring();
   if (!path) {
     return nullptr;
   }
diff --git a/layout/svg/nsSVGClipPathFrame.cpp b/layout/svg/nsSVGClipPathFrame.cpp
index f718cc2b7417..6f4416e829da 100644
--- a/layout/svg/nsSVGClipPathFrame.cpp
+++ b/layout/svg/nsSVGClipPathFrame.cpp
@@ -66,10 +66,8 @@ nsSVGClipPathFrame::ApplyClipOrPaintClipMask(nsRenderingContext* aContext,
           gfx->CurrentMatrix().PreMultiply(toChildsUserSpace).NudgeToIntegers();
         if (!newMatrix.IsSingular()) {
           gfx->SetMatrix(newMatrix);
-          RefPtr<PathBuilder> builder =
-            gfx->GetDrawTarget()->CreatePathBuilder(
-              nsSVGUtils::ToFillRule(pathFrame->StyleSVG()->mClipRule));
-          clipPath = pathElement->BuildPath(builder);
+          clipPath = pathElement->GetOrBuildPath(*gfx->GetDrawTarget(),
+                                                 nsSVGUtils::ToFillRule(pathFrame->StyleSVG()->mClipRule));
         }
       }
     }
diff --git a/layout/svg/nsSVGPathGeometryFrame.cpp b/layout/svg/nsSVGPathGeometryFrame.cpp
index 6715bff3b251..6ae36142a9f4 100644
--- a/layout/svg/nsSVGPathGeometryFrame.cpp
+++ b/layout/svg/nsSVGPathGeometryFrame.cpp
@@ -158,6 +158,25 @@ nsSVGPathGeometryFrame::DidSetStyleContext(nsStyleContext* aOldStyleContext)
       // nsDisplayOpacity display list item, so DLBI won't invalidate for us.
       InvalidateFrame();
     }
+
+    nsSVGPathGeometryElement* element =
+      static_cast<nsSVGPathGeometryElement*>(mContent);
+
+    if (aOldStyleContext->PeekStyleSVG()) {
+      if ((StyleSVG()->mStrokeLinecap !=
+             aOldStyleContext->PeekStyleSVG()->mStrokeLinecap) &&
+          element->Tag() == nsGkAtoms::path) {
+        // If the stroke-linecap changes to or from "butt" then our element
+        // needs to update its cached Moz2D Path, since SVGPathData::BuildPath
+        // decides whether or not to insert little lines into the path for zero
+        // length subpaths base on that property.
+        element->ClearAnyCachedPath();
+      } else if (StyleSVG()->mFillRule !=
+                   aOldStyleContext->PeekStyleSVG()->mFillRule) {
+        // Moz2D Path objects are fill-rule specific.
+        element->ClearAnyCachedPath();
+      }
+    }
   }
 }
 
@@ -288,9 +307,7 @@ nsSVGPathGeometryFrame::GetFrameForPoint(const gfxPoint& aPoint)
   // so that we get more consistent/backwards compatible results?
   RefPtr<DrawTarget> drawTarget =
     gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget();
-  RefPtr<PathBuilder> builder =
-    drawTarget->CreatePathBuilder(fillRule);
-  RefPtr<Path> path = content->BuildPath(builder);
+  RefPtr<Path> path = content->GetOrBuildPath(*drawTarget, fillRule);
   if (!path) {
     return nullptr; // no path, so we don't paint anything that can be hit
   }
@@ -410,6 +427,7 @@ nsSVGPathGeometryFrame::NotifySVGChanged(uint32_t aFlags)
     // mRect.
     if (static_cast<nsSVGPathGeometryElement*>(mContent)->GeometryDependsOnCoordCtx() ||
         StyleSVG()->mStrokeWidth.HasPercent()) {
+      static_cast<nsSVGPathGeometryElement*>(mContent)->ClearAnyCachedPath();
       nsSVGUtils::ScheduleReflowSVG(this);
     }
   }
@@ -454,8 +472,7 @@ nsSVGPathGeometryFrame::GetBBoxContribution(const Matrix &aToBBoxUserspace,
 
   FillRule fillRule = StyleSVG()->mFillRule == NS_STYLE_FILL_RULE_NONZERO
                         ? FillRule::FILL_WINDING : FillRule::FILL_EVEN_ODD;
-  RefPtr<PathBuilder> builder = tmpDT->CreatePathBuilder(fillRule);
-  RefPtr<Path> pathInUserSpace = element->BuildPath(builder);
+  RefPtr<Path> pathInUserSpace = element->GetOrBuildPath(*tmpDT, fillRule);
   if (!pathInUserSpace) {
     return bbox;
   }
@@ -463,7 +480,7 @@ nsSVGPathGeometryFrame::GetBBoxContribution(const Matrix &aToBBoxUserspace,
   if (aToBBoxUserspace.IsIdentity()) {
     pathInBBoxSpace = pathInUserSpace;
   } else {
-    builder =
+    RefPtr<PathBuilder> builder =
       pathInUserSpace->TransformedCopyToBuilder(aToBBoxUserspace, fillRule);
     pathInBBoxSpace = builder->Finish();
     if (!pathInBBoxSpace) {
@@ -663,13 +680,10 @@ nsSVGPathGeometryFrame::Render(gfxContext* aContext,
     nsSVGUtils::ToFillRule(renderMode == SVGAutoRenderState::NORMAL ?
                              StyleSVG()->mFillRule : StyleSVG()->mClipRule);
 
-  RefPtr<PathBuilder> builder = drawTarget->CreatePathBuilder(fillRule);
-  if (!builder) {
-    return;
-  }
+  nsSVGPathGeometryElement* element =
+    static_cast<nsSVGPathGeometryElement*>(mContent);
 
-  RefPtr<Path> path =
-    static_cast<nsSVGPathGeometryElement*>(mContent)->BuildPath(builder);
+  RefPtr<Path> path = element->GetOrBuildPath(*drawTarget, fillRule);
   if (!path) {
     return;
   }
@@ -715,7 +729,8 @@ nsSVGPathGeometryFrame::Render(gfxContext* aContext,
       gfxMatrix outerSVGToUser = userToOuterSVG;
       outerSVGToUser.Invert();
       aContext->Multiply(outerSVGToUser);
-      builder = path->TransformedCopyToBuilder(ToMatrix(userToOuterSVG), fillRule);
+      RefPtr<PathBuilder> builder =
+        path->TransformedCopyToBuilder(ToMatrix(userToOuterSVG), fillRule);
       path = builder->Finish();
     }
     GeneralPattern strokePattern;
diff --git a/layout/svg/nsSVGUtils.cpp b/layout/svg/nsSVGUtils.cpp
index 1bc40d0a08a9..05a071f88d28 100644
--- a/layout/svg/nsSVGUtils.cpp
+++ b/layout/svg/nsSVGUtils.cpp
@@ -57,10 +57,17 @@ using namespace mozilla;
 using namespace mozilla::dom;
 using namespace mozilla::gfx;
 
+static bool sSVGPathCachingEnabled;
 static bool sSVGDisplayListHitTestingEnabled;
 static bool sSVGDisplayListPaintingEnabled;
 static bool sSVGNewGetBBoxEnabled;
 
+bool
+NS_SVGPathCachingEnabled()
+{
+  return sSVGPathCachingEnabled;
+}
+
 bool
 NS_SVGDisplayListHitTestingEnabled()
 {
@@ -137,6 +144,9 @@ SVGAutoRenderState::IsPaintingToWindow(DrawTarget* aDrawTarget)
 void
 nsSVGUtils::Init()
 {
+  Preferences::AddBoolVarCache(&sSVGPathCachingEnabled,
+                               "svg.path-caching.enabled");
+
   Preferences::AddBoolVarCache(&sSVGDisplayListHitTestingEnabled,
                                "svg.display-lists.hit-testing.enabled");
 
diff --git a/layout/svg/nsSVGUtils.h b/layout/svg/nsSVGUtils.h
index 8e7bf533ffbf..b3e4f79a33ba 100644
--- a/layout/svg/nsSVGUtils.h
+++ b/layout/svg/nsSVGUtils.h
@@ -78,6 +78,7 @@ class SourceSurface;
 #define SVG_HIT_TEST_CHECK_MRECT 0x04
 
 
+bool NS_SVGPathCachingEnabled();
 bool NS_SVGDisplayListHitTestingEnabled();
 bool NS_SVGDisplayListPaintingEnabled();
 bool NS_SVGNewGetBBoxEnabled();
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index ebb5a8e8b99e..af2c7c316f7f 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -2291,6 +2291,9 @@ pref("dom.ipc.plugins.unloadTimeoutSecs", 30);
 
 pref("dom.ipc.processCount", 1);
 
+// Enable caching of Moz2D Path objects for SVG geometry elements
+pref("svg.path-caching.enabled", true);
+
 // Enable the use of display-lists for SVG hit-testing and painting.
 pref("svg.display-lists.hit-testing.enabled", true);
 pref("svg.display-lists.painting.enabled", true);