Fix race in shadow tessellation by deep copying task params

    ShadowTask(const Matrix4* drawTransform, const Rect& localClip, bool opaque,

            const SkPath* casterPerimeter, const Matrix4* transformXY, const Matrix4* transformZ,

            const Vector3& lightCenter, float lightRadius)

        : drawTransform(drawTransform)

        : drawTransform(*drawTransform)

        , localClip(localClip)

        , opaque(opaque)

        , casterPerimeter(casterPerimeter)

        , transformXY(transformXY)

        , transformZ(transformZ)

        , casterPerimeter(*casterPerimeter)

        , transformXY(*transformXY)

        , transformZ(*transformZ)

        , lightCenter(lightCenter)

        , lightRadius(lightRadius) {

    }

        delete bufferPair;

    }

    // Note - only the localClip is deep copied, since other pointers point at Allocator controlled

    // objects, which are safe for the entire frame

    const Matrix4* drawTransform;

    /* Note - we deep copy all task parameters, because *even though* pointers into Allocator

     * controlled objects (like the SkPath and Matrix4s) should be safe for the entire frame,

     * certain Allocators are destroyed before trim() is called to flush incomplete tasks.

     *

     * These deep copies could be avoided, long term, by cancelling or flushing outstanding tasks

     * before tearning down single-frame LinearAllocators.

     */

    const Matrix4 drawTransform;

    const Rect localClip;

    bool opaque;

    const SkPath* casterPerimeter;

    const Matrix4* transformXY;

    const Matrix4* transformZ;

    const SkPath casterPerimeter;

    const Matrix4 transformXY;

    const Matrix4 transformZ;

    const Vector3 lightCenter;

    const float lightRadius;

};

        VertexBuffer* ambientBuffer = new VertexBuffer;

        VertexBuffer* spotBuffer = new VertexBuffer;

        tessellateShadows(t->drawTransform, &t->localClip, t->opaque, t->casterPerimeter,

                t->transformXY, t->transformZ, t->lightCenter, t->lightRadius,

        tessellateShadows(&t->drawTransform, &t->localClip, t->opaque, &t->casterPerimeter,

                &t->transformXY, &t->transformZ, t->lightCenter, t->lightRadius,

                *ambientBuffer, *spotBuffer);

        t->setResult(new TessellationCache::vertexBuffer_pair_t(ambientBuffer, spotBuffer));