Refactors androidx.compose.animation:animation to the androidx.compose.animation package name

Also moves ui-animation-tooling-internal to androidx.compose.animation.tooling

Bug: b/160233169
Test: ./gradlew checkApi
Relnote: N/A
Change-Id: I3a83bf5c4c44cb7ef24c2033897943acb5ee5cbd

diff --git a/ui/ui-animation/src/androidAndroidTest/kotlin/androidx/compose/animation/AnimationModifierTest.kt b/ui/ui-animation/src/androidAndroidTest/kotlin/androidx/compose/animation/AnimationModifierTest.kt
new file mode 100644
index 0000000..b66422a
--- /dev/null
+++ b/ui/ui-animation/src/androidAndroidTest/kotlin/androidx/compose/animation/AnimationModifierTest.kt

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.animation
+
+import androidx.compose.animation.core.LinearOutSlowInEasing
+import androidx.compose.animation.core.tween
+import androidx.compose.foundation.Box
+import androidx.compose.foundation.layout.size
+import androidx.compose.getValue
+import androidx.compose.mutableStateOf
+import androidx.compose.setValue
+import androidx.test.filters.MediumTest
+import androidx.ui.core.Constraints
+import androidx.ui.core.DensityAmbient
+import androidx.ui.core.LayoutDirection
+import androidx.ui.core.LayoutModifier
+import androidx.ui.core.Measurable
+import androidx.ui.core.MeasureScope
+import androidx.ui.core.Modifier
+import androidx.ui.test.createComposeRule
+import androidx.ui.test.runOnIdle
+import androidx.ui.test.waitForIdle
+import androidx.ui.unit.dp
+import junit.framework.TestCase.assertEquals
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+@RunWith(JUnit4::class)
+@MediumTest
+class AnimationModifierTest {
+
+    @get:Rule
+    val composeTestRule = createComposeRule()
+
+    @Test
+    fun animateContentSizeTest() {
+        val startWidth = 100
+        val endWidth = 150
+        val startHeight = 400
+        val endHeight = 200
+        var width by mutableStateOf(startWidth)
+        var height by mutableStateOf(startHeight)
+
+        var density = 0f
+        val testModifier by mutableStateOf(TestModifier())
+
+        composeTestRule.clockTestRule.pauseClock()
+        composeTestRule.setContent {
+            Box(
+                testModifier + Modifier.animateContentSize(
+                    tween(
+                        200, easing = LinearOutSlowInEasing
+                    )
+                ).size(
+                    width.dp, height.dp
+                )
+            )
+            density = DensityAmbient.current.density
+        }
+
+        runOnIdle {
+            width = endWidth
+            height = endHeight
+        }
+        waitForIdle()
+
+        for (i in 0..200 step 20) {
+            val fraction = LinearOutSlowInEasing.invoke(i / 200f)
+            assertEquals(
+                density * (startWidth * (1 - fraction) + endWidth * fraction),
+                testModifier.width.toFloat(), 1f
+            )
+
+            assertEquals(
+                density * (startHeight * (1 - fraction) + endHeight * fraction),
+                testModifier.height.toFloat(), 1f
+            )
+
+            composeTestRule.clockTestRule.advanceClock(20)
+            waitForIdle()
+        }
+    }
+}
+
+private class TestModifier : LayoutModifier {
+    var width: Int = 0
+    var height: Int = 0
+    override fun MeasureScope.measure(
+        measurable: Measurable,
+        constraints: Constraints,
+        layoutDirection: LayoutDirection
+    ): MeasureScope.MeasureResult {
+        val placeable = measurable.measure(constraints)
+        width = placeable.width
+        height = placeable.height
+        return layout(width, height) {
+            placeable.place(0, 0)
+        }
+    }
+}