Since your ultimate goal is to make a chart, you may want to pivot the data so that each fruit is in its own column.
Assuming the data is in Sheet1!A2:B, choose Insert > New sheet and enter this array formula in cell A2 of the new sheet:
=query(
Sheet1!A2:C,
"select A, max(C)
where A is not null
group by A
pivot B",
0
)
Then create a chart based on the data in the new sheet.
If you really need to expand the data so that every date and fruit has a value, and that value is zero when no value appears in the source data, insert yet another sheet and enter this array formula in cell A2 of the new sheet:
=arrayformula( query( split( flatten( unique(trim(Sheet1!A2:A)) & "µ" & transpose(unique(Sheet1!B2:B)) ), "µ" ), "where Col1 is not null and Col2 is not null", 0 ) )
...and this formula in cell C2:
=arrayformula( iferror( vlookup(A2:A & B2:B, { Sheet1!A2:A & Sheet1!B2:B, Sheet1!C2:C }, 2, false), if(Sheet1!A2:A, 0, iferror(1/0)) ) )