[Slider][RangeSlider] valueFrom and valueTo can have the same value

[manabu-nakamura]

closes #2787

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">
    <com.google.android.material.slider.Slider
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:valueFrom="0"
        android:valueTo="2"
        app:labelBehavior="visible" />
    <com.google.android.material.slider.Slider
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:valueFrom="0"
        android:valueTo="2"
        android:stepSize="1"
        app:labelBehavior="visible" />
    <com.google.android.material.slider.RangeSlider
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:valueFrom="0"
        android:valueTo="2"
        app:values="@array/initial_slider_values"
        app:labelBehavior="visible" />
    <com.google.android.material.slider.Slider
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:valueFrom="0"
        android:valueTo="0"
        app:labelBehavior="visible" />
    <com.google.android.material.slider.Slider
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:valueFrom="0"
        android:valueTo="0"
        android:stepSize="1"
        app:labelBehavior="visible" />
    <com.google.android.material.slider.RangeSlider
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:valueFrom="0"
        android:valueTo="0"
        app:values="@array/initial_slider_values"
        app:labelBehavior="visible" />
</LinearLayout>

<resources>
    <array name="initial_slider_values">
        <item>0</item>
        <item>0</item>
    </array>
</resources>

(Compose)

[drchen]

I'm reluctant about the change as it may break a bunch of logic. Dan, can take a look?

[akhbulatov]

Any progress?

[manabu-nakamura]

Discussion
https://m3.material.io/components/sliders/specs
https://m3.material.io/components/sliders/overview#f816e17e-2386-4edc-b7d1-10bffe48d0a9:

Sliders should present the full range of choices that are available

• When android:valueFrom == android:valueTo, the slider doesn't present both the inactive track and the inactive track stop indicator.
  
• When android:valueFrom == android:valueTo, the slider presents the inactive track but doesn't present the inactive track stop indicator.
  
• (Compose) When valueRange = 0f..0f, the slider presents both the inactive track and the inactive track stop indicator.