--- a/dom/canvas/DrawTargetWebgl.cpp
+++ b/dom/canvas/DrawTargetWebgl.cpp
@@ -1388,23 +1388,25 @@ bool DrawTargetWebgl::SharedContext::Dra
       if (mDirtyViewport) {
         float viewportData[2] = {float(mViewportSize.width),
                                  float(mViewportSize.height)};
         mWebgl->UniformData(
             LOCAL_GL_FLOAT_VEC2, mSolidProgramViewport, false,
             {(const uint8_t*)viewportData, sizeof(viewportData)});
         mDirtyViewport = false;
       }
-      if (mDirtyAA) {
-        // AA is not supported for OP_SOURCE.
+      if (mDirtyAA || aStrokeOptions) {
+        // AA is not supported for OP_SOURCE. Native lines use line smoothing.
         float aaData =
-            mLastCompositionOp == CompositionOp::OP_SOURCE ? 0.0f : 1.0f;
+            mLastCompositionOp == CompositionOp::OP_SOURCE || aStrokeOptions
+                ? 0.0f
+                : 1.0f;
         mWebgl->UniformData(LOCAL_GL_FLOAT, mSolidProgramAA, false,
                             {(const uint8_t*)&aaData, sizeof(aaData)});
-        mDirtyAA = false;
+        mDirtyAA = !!aStrokeOptions;
       }
       float a = color.a * aOptions.mAlpha;
       float colorData[4] = {color.b * a, color.g * a, color.r * a, a};
       Matrix xform(aRect.width, 0.0f, 0.0f, aRect.height, aRect.x, aRect.y);
       if (aTransformed) {
         xform *= currentTransform;
       }
       float xformData[6] = {xform._11, xform._12, xform._21,
@@ -1582,23 +1584,25 @@ bool DrawTargetWebgl::SharedContext::Dra
       if (mDirtyViewport) {
         float viewportData[2] = {float(mViewportSize.width),
                                  float(mViewportSize.height)};
         mWebgl->UniformData(
             LOCAL_GL_FLOAT_VEC2, mImageProgramViewport, false,
             {(const uint8_t*)viewportData, sizeof(viewportData)});
         mDirtyViewport = false;
       }
-      if (mDirtyAA) {
-        // AA is not supported for OP_SOURCE.
+      if (mDirtyAA || aStrokeOptions) {
+        // AA is not supported for OP_SOURCE. Native lines use line smoothing.
         float aaData =
-            mLastCompositionOp == CompositionOp::OP_SOURCE ? 0.0f : 1.0f;
+            mLastCompositionOp == CompositionOp::OP_SOURCE || aStrokeOptions
+                ? 0.0f
+                : 1.0f;
         mWebgl->UniformData(LOCAL_GL_FLOAT, mImageProgramAA, false,
                             {(const uint8_t*)&aaData, sizeof(aaData)});
-        mDirtyAA = false;
+        mDirtyAA = !!aStrokeOptions;
       }
       DeviceColor color = aMaskColor.valueOr(DeviceColor(1, 1, 1, 1));
       float a = color.a * aOptions.mAlpha;
       float colorData[4] = {color.b * a, color.g * a, color.r * a, a};
       float swizzleData = aMaskColor ? 1.0f : 0.0f;
       Matrix xform(aRect.width, 0.0f, 0.0f, aRect.height, aRect.x, aRect.y);
       if (aTransformed) {
         xform *= currentTransform;