Do not reset the ContentLayer and contentsOpaque for canvas and media elements

Do not reset the ContentLayer and contentsOpaque for canvas and media elements

[Title] Do not reset the ContentLayer and contentsOpaque for canvas and media elements
[Issue#] N_SE-41346
[Problem] Canvas element disappers when tapping outside the canvas.
[Cause] ContentsLayer set to NULL and lost the original canvas content.
	And ContentsOpaque is set to 1, because of that background color is not painted after that.
[Solution] Do not set ContentsLayer to NULL and donot change the contentsOpaque
           for canvas and media layers

Change-Id: I57afb45793ff087387dc315998493e2bb9992528