fill the interior of a randomly constructed closed path

Question

I am not sure how to proceed in filling the interior of a randomly generated (via a random decoration) path.

I began with code given in the answer to this question and worked on it since the basic purpose was related.

The fill and the drawn line are not quite the same, because there is a random decoration applied to each.

QUESTION)

How do I apply the fill to the interior bounded by the drawn line?

(Also, by the way, in this case, how do I make the decoration arrows larger? Can I apply decoration arrows also the drawn path without breaking the other decoration?)

\documentclass[border=0pt]{standalone}\usepackage{mathtools,tikz,tkz-euclide}\usetikzlibrary{decorations.markings,arrows,decorations.pathmorphing}\usetkzobj{all}\begin{document}\begin{tikzpicture}[label]\tkzInit[xmin=-0.8,xmax=10,ymin=-0.4,ymax=8.4] \tkzClip
\tikzset{every node}=[font=\normalsize]

%here_we_make_such_a_dashing
\tikzstyle{finelydashed}=[dash pattern=on 4pt off 7pt]
\tikzstyle{coarselydashed}=[dash pattern=on 7pt off 8pt]

%here_we_make_such_a_shading
\pgfdeclarepatternformonly{ltrdiagonals}%
{\pgfqpoint{-1pt}{-1pt}}{\pgfqpoint{10pt}{10pt}}%
{\pgfqpoint{9pt}{9pt}}{\pgfsetlinewidth{0.4pt}\pgfpathmoveto{\pgfqpoint{0pt}{0pt}}%
\pgfpathlineto{\pgfqpoint{9.1pt}{9.1pt}}%
\pgfusepath{stroke}}%

%here_we_make_such_a_grid
\draw[help lines,color=black!90](0,0)grid(8,8);

%here_we_define_our_several_points
\tkzDefPoint(1,2){v}\tkzDefPoint(7,2){w}  
\tkzDefPointBy[rotation=center w angle -42](v)
\tkzGetPoint{C}
\tkzDefPointBy[rotation=center v angle 63](w)
\tkzGetPoint{D}
\tkzInterLL(v,D)(C,w)\tkzGetPoint{x}


\tkzDefMidPoint(v,x)\tkzGetPoint{M}

\draw[shade,top color=black!96,bottom color=black!16,fill opacity=0.64,decoration=   {random steps,segment length=22pt,amplitude=11pt},decorate,line width=2pt,rounded corners=8pt](v)--(1.7,3.2)--(4,4)--(6,3)--(w)--(7.4,1)--(0.4,0.4)--(v);
\fill[even odd rule,pattern=ltrdiagonals,pattern color=black!84,decoration={random steps,segment length=24pt,amplitude=0.24cm},decorate,line width=2pt,rounded corners=8pt](v)--(1.7,3.2)--(4,4)--(6,3)--(w)--(7.4,1)--(0.4,0.4)--(v);

%here_we_label_each_node_so
\tkzLabelPoint[above left](v){\LARGE $\boldsymbol{\mathbf{H}_{\;n\;v}}\,$}
\tkzLabelPoint[above left](x){\LARGE $\mathbf{x_{\;n}}$}  
\tkzLabelPoint[right](w){\LARGE $\;\boldsymbol{\mathbf{H}_{\;n\;w}}$}
\tkzLabelAngle[pos=0.64](v,x,w){\large $\boldsymbol{\varphi}$}
\tkzLabelAngle[pos=0.64](w,v,x){\large $\boldsymbol{\rho}$}
\tkzLabelPoint[left](M){$\boldsymbol{2\cdot\mu}\;$}

%here_we_construct_each_line_so
\begin{scope}[decoration={markings,mark=at position 0.5 with {\LARGE\arrow{triangle 45},color=black!96}}]
\draw[-,decorate](v)--(x);
\draw[-,decorate](v)--(w);
\draw[-,decorate](x)--(w);
\end{scope}
\draw[-,line width=1.2pt,coarselydashed,color=black!96](v)--(x);
\draw[-,line width=1.2pt,coarselydashed,color=black!96](v)--(w);
\draw[-,line width=1.2pt,coarselydashed,color=black!96](x)--(w);
\tkzDrawPoints[color=black,shape=circle,fill=black!64,size=16pt](v,x,w)
\tkzMarkAngle[scale=1,line width=1.2pt,finelydashed,color=black!96](v,x,w)
\tkzMarkAngle[scale=1,line width=1.2pt,finelydashed,color=black!96](w,v,x)
\end{tikzpicture}\end{document}

Answer 1

You need to reuse the same path with postaction,preaction keys.

\documentclass[border=0pt]{standalone}
\usepackage{mathtools,tikz,tkz-euclide}\usetikzlibrary{decorations.markings,arrows,decorations.pathmorphing}
\usetkzobj{all}
\begin{document}
\begin{tikzpicture}[label]
\tkzInit[xmin=-0.8,xmax=10,ymin=-0.4,ymax=8.4] 
\tkzClip
\tikzset{every node}=[font=\normalsize]
%here_we_make_such_a_dashing
\tikzstyle{finelydashed}=[dash pattern=on 4pt off 7pt]
\tikzstyle{coarselydashed}=[dash pattern=on 7pt off 8pt]

%here_we_make_such_a_shading
\pgfdeclarepatternformonly{ltrdiagonals}%
{\pgfqpoint{-1pt}{-1pt}}{\pgfqpoint{10pt}{10pt}}%
{\pgfqpoint{9pt}{9pt}}{\pgfsetlinewidth{0.4pt}\pgfpathmoveto{\pgfqpoint{0pt}{0pt}}%
\pgfpathlineto{\pgfqpoint{9.1pt}{9.1pt}}%
\pgfusepath{stroke}}%

%here_we_make_such_a_grid
\draw[help lines,color=black!90](0,0)grid(8,8);

%here_we_define_our_several_points
\tkzDefPoint(1,2){v}\tkzDefPoint(7,2){w}  
\tkzDefPointBy[rotation=center w angle -42](v)
\tkzGetPoint{C}
\tkzDefPointBy[rotation=center v angle 63](w)
\tkzGetPoint{D}
\tkzInterLL(v,D)(C,w)\tkzGetPoint{x}


\tkzDefMidPoint(v,x)\tkzGetPoint{M}

\draw[%shade,
     top color=black!96,
     bottom color=black!16,
     fill opacity=0.64,
     decoration={random steps,segment length=22pt,amplitude=11pt},
     decorate,
     line width=2pt,
     rounded corners=8pt,
     postaction={fill,pattern=ltrdiagonals,pattern color=black!84}
     ](v)--(1.7,3.2)--(4,4)--(6,3)--(w)--(7.4,1)--(0.4,0.4)--(v);


%here_we_label_each_node_so
\tkzLabelPoint[above left](v){\LARGE $\boldsymbol{\mathbf{H}_{\;n\;v}}\,$}
\tkzLabelPoint[above left](x){\LARGE $\mathbf{x_{\;n}}$}  
\tkzLabelPoint[right](w){\LARGE $\;\boldsymbol{\mathbf{H}_{\;n\;w}}$}
\tkzLabelAngle[pos=0.64](v,x,w){\large $\boldsymbol{\varphi}$}
\tkzLabelAngle[pos=0.64](w,v,x){\large $\boldsymbol{\rho}$}
\tkzLabelPoint[left](M){$\boldsymbol{2\cdot\mu}\;$}

%here_we_construct_each_line_so
\begin{scope}[decoration={markings,mark=at position 0.5 with {\LARGE\arrow{triangle 45},color=black!96}}]
\draw[-,decorate](v)--(x);
\draw[-,decorate](v)--(w);
\draw[-,decorate](x)--(w);
\end{scope}
\draw[-,line width=1.2pt,coarselydashed,color=black!96](v)--(x);
\draw[-,line width=1.2pt,coarselydashed,color=black!96](v)--(w);
\draw[-,line width=1.2pt,coarselydashed,color=black!96](x)--(w);
\tkzDrawPoints[color=black,shape=circle,fill=black!64,size=16pt](v,x,w)
\tkzMarkAngle[scale=1,line width=1.2pt,finelydashed,color=black!96](v,x,w)
\tkzMarkAngle[scale=1,line width=1.2pt,finelydashed,color=black!96](w,v,x)
\end{tikzpicture}
\end{document}

As you can see random steps don't play well with the rounded corners option. Also have a look at Should \tikzset or \tikzstyle be used to define TikZ styles?