diff --git a/dom/base/DOMMatrix.cpp b/dom/base/DOMMatrix.cpp
index 56cf6f1b17..f2dbe2a2a7 100644
--- a/dom/base/DOMMatrix.cpp
+++ b/dom/base/DOMMatrix.cpp
@@ -129,17 +129,12 @@ DOMMatrixReadOnly::SetDataFromMatrix2DInit(const DOMMatrix2DInit& aMatrixInit) {
 }
 
 void
-DOMMatrixReadOnly::SetDataFromMatrixInit(DOMMatrixInit& aMatrixInit)
+DOMMatrixReadOnly::SetDataFromMatrixInit(const DOMMatrixInit& aMatrixInit)
 {
   const bool is2D = aMatrixInit.mIs2D.Value();
   MOZ_ASSERT(is2D == Is2D());
   if (is2D) {
-    mMatrix2D->_11 = aMatrixInit.mM11.Value();
-    mMatrix2D->_12 = aMatrixInit.mM12.Value();
-    mMatrix2D->_21 = aMatrixInit.mM21.Value();
-    mMatrix2D->_22 = aMatrixInit.mM22.Value();
-    mMatrix2D->_31 = aMatrixInit.mM41.Value();
-    mMatrix2D->_32 = aMatrixInit.mM42.Value();
+    SetDataFromMatrix2DInit(aMatrixInit);
   } else {
     mMatrix3D->_11 = aMatrixInit.mM11.Value();
     mMatrix3D->_12 = aMatrixInit.mM12.Value();
diff --git a/dom/base/DOMMatrix.h b/dom/base/DOMMatrix.h
index 423580e2c4..9e961de7b4 100644
--- a/dom/base/DOMMatrix.h
+++ b/dom/base/DOMMatrix.h
@@ -52,6 +52,11 @@ public:
     mMatrix3D = new gfx::Matrix4x4(aMatrix);
   }
 
+  DOMMatrixReadOnly(nsISupports* aParent, const gfx::Matrix& aMatrix)
+    : mParent(aParent) {
+    mMatrix2D = new gfx::Matrix(aMatrix);
+  }
+
   NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(DOMMatrixReadOnly)
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(DOMMatrixReadOnly)
 
@@ -234,7 +239,7 @@ protected:
    * The init dictionary's dimension must match the matrix one.
    */
   void SetDataFromMatrix2DInit(const DOMMatrix2DInit& aMatrixInit);
-  void SetDataFromMatrixInit(DOMMatrixInit& aMatrixInit);
+  void SetDataFromMatrixInit(const DOMMatrixInit& aMatrixInit);
 
   DOMMatrixReadOnly* SetMatrixValue(const nsAString& aTransformList, ErrorResult& aRv);
   void Ensure3DMatrix();
@@ -268,6 +273,10 @@ public:
     : DOMMatrixReadOnly(aParent, aMatrix)
   {}
 
+  DOMMatrix(nsISupports* aParent, const gfx::Matrix& aMatrix)
+    : DOMMatrixReadOnly(aParent, aMatrix)
+  {}
+
   static already_AddRefed<DOMMatrix>
   FromMatrix(nsISupports* aParent, const DOMMatrixInit& aMatrixInit, ErrorResult& aRv);
   static already_AddRefed<DOMMatrix>
diff --git a/dom/canvas/CanvasRenderingContext2D.cpp b/dom/canvas/CanvasRenderingContext2D.cpp
index 60078a8fcb..d134cfade1 100644
--- a/dom/canvas/CanvasRenderingContext2D.cpp
+++ b/dom/canvas/CanvasRenderingContext2D.cpp
@@ -2229,6 +2229,18 @@ CanvasRenderingContext2D::Transform(double aM11, double aM12, double aM21,
   SetTransformInternal(newMatrix);
 }
 
+already_AddRefed<DOMMatrix>
+CanvasRenderingContext2D::GetTransform(ErrorResult& aError) {
+  EnsureTarget();
+  if (!IsTargetValid()) {
+    aError.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+  RefPtr<DOMMatrix> matrix =
+      new DOMMatrix(GetParentObject(), mTarget->GetTransform());
+  return matrix.forget();
+}
+
 void
 CanvasRenderingContext2D::SetTransform(double aM11, double aM12,
                                        double aM21, double aM22,
@@ -2244,6 +2256,22 @@ CanvasRenderingContext2D::SetTransform(double aM11, double aM12,
   SetTransformInternal(Matrix(aM11, aM12, aM21, aM22, aDx, aDy));
 }
 
+void
+CanvasRenderingContext2D::SetTransform(const DOMMatrix2DInit& aInit,
+                                       ErrorResult& aError) {
+  TransformWillUpdate();
+  if (!IsTargetValid()) {
+    aError.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  RefPtr<DOMMatrixReadOnly> matrix =
+      DOMMatrixReadOnly::FromMatrix(GetParentObject(), aInit, aError);
+  if (!aError.Failed()) {
+    SetTransformInternal(Matrix(*(matrix->GetInternal2D())));
+  }
+}
+
 void
 CanvasRenderingContext2D::SetTransformInternal(const Matrix& aTransform)
 {
diff --git a/dom/canvas/CanvasRenderingContext2D.h b/dom/canvas/CanvasRenderingContext2D.h
index d4f295a03f..81637e8eb6 100644
--- a/dom/canvas/CanvasRenderingContext2D.h
+++ b/dom/canvas/CanvasRenderingContext2D.h
@@ -57,6 +57,10 @@ class CanvasRenderingContext2DUserData;
 class CanvasDrawObserver;
 class CanvasShutdownObserver;
 
+class DOMMatrix;
+class DOMMatrixReadOnly;
+struct DOMMatrix2DInit;
+
 /**
  ** CanvasRenderingContext2D
  **/
@@ -88,8 +92,10 @@ public:
   void Translate(double aX, double aY, mozilla::ErrorResult& aError);
   void Transform(double aM11, double aM12, double aM21, double aM22, double aDx,
                  double aDy, mozilla::ErrorResult& aError);
+  already_AddRefed<DOMMatrix> GetTransform(mozilla::ErrorResult& aError);
   void SetTransform(double aM11, double aM12, double aM21, double aM22, double aDx,
                     double aDy, mozilla::ErrorResult& aError);
+  void SetTransform(const DOMMatrix2DInit& aInit, mozilla::ErrorResult& aError);
   void ResetTransform(mozilla::ErrorResult& aError);
 
   double GlobalAlpha()