849: Mainline

Just as the meterValueHolder getter creates a new value holder the first time that it is sent, the meterViewHolder getter creates a new meter the first time that it is sent:

MeterDemonstration method definition • instance 
meterViewHolder 
  ^ meterViewHolder isNil 
      ifTrue: [meterViewHolder := Meter new. 
               meterViewHolder min: 0; max: 10; title: 'Test Meter'. 
               meterViewHolder model: self meterValueHolder. 
               meterViewHolder] 
      ifFalse: [meterViewHolder] 

Note that, the first time that it is sent, meterViewHolder getter also does the following:

• Initialize the instance variables of the new meter using setters.
• Set the value of the new meter's model instance variable to be the same as the value of the meterValueHolder instance variable.