perf(cdkTextareaAutosize): Skip height measurements when textarea value is empty

[kseamon]

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

Calls to _measureScrollHeight, which trigger css layout, are not needed when there's nothing in the text field. In this case, simply set the height to 1 row (height of one line).

See internal CL 421826236 for more context.

Reproduction

Steps to reproduce:

1. Bootstrap a textarea with cdkTextareaAutosize that has value of '' (empty)

Expected Behavior

_measureScrollHeight() called only when there's a non-empty value.

Actual Behavior

_measureScrollHeight() is called regardless of value.

Environment

• Angular: 13
• CDK/Material: 13
• Browser(s): All
• Operating System (e.g. Windows, macOS, Ubuntu): All