Clear InputMethodManager.sInstance for SDK > P

This fixes a minor case of test pollution when a test interacts with a
TextView.

InputMethodManager.sInstance still gets populated in SDK > P, and it may
contain a reference to a ViewRootImpl (mCurRootView), which causes an Activity
to leak across tests.

PiperOrigin-RevId: 411153919

integration_tests/androidx_test/src/main/AndroidManifest-NoTestPackageActivities.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Manifest for ATSL integration tests
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.robolectric.integration.axt">
+    <uses-sdk android:targetSdkVersion="28"/>
+
+    <uses-permission android:name="android.permission.READ_CONTACTS"/>
+
+    <application>
+        <activity android:name="org.robolectric.integrationtests.axt.EspressoActivity"
+                  android:label="Activity Label"
+                  android:exported="true" />
+        <activity android:name="org.robolectric.integrationtests.axt.ActivityWithPlatformMenu"
+            android:exported="true">
+        </activity>
+        <activity android:name="org.robolectric.integrationtests.axt.ActivityWithAppCompatMenu"
+            android:exported="true"
+            android:theme="@style/Theme.AppCompat" />
+        <activity android:name="org.robolectric.integrationtests.axt.AppCompatActivityWithToolbarMenu"
+            android:exported="true"
+            android:theme="@style/Theme.AppCompat.NoActionBar" />
+        <activity android:name="org.robolectric.integrationtests.axt.ActivityWithSwitchCompat"
+            android:exported="true"
+            android:theme="@style/Theme.AppCompat" />
+        <activity android:name="org.robolectric.integrationtests.axt.StubBrowserActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+                <data android:scheme="http" />
+                <data android:scheme="https" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

integration_tests/androidx_test/src/test/AndroidManifest-NoTestPackageActivities.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.robolectric.integrationtests.axt">
+
+  <uses-sdk
+      android:minSdkVersion="14"
+      android:targetSdkVersion="27"/>
+
+  <application>
+    <activity android:name=".EspressoActivity" android:exported="true"/>
+  </application>
+
+  <instrumentation
+      android:name="androidx.test.runner.AndroidJUnitRunner"
+      android:targetPackage="org.robolectric.integration.axt"/>
+
+</manifest>

shadows/framework/src/main/java/org/robolectric/shadows/ShadowInputMethodManager.java

@@ -267,9 +267,10 @@ public static void reset() {
     _InputMethodManager_ _reflector = reflector(_InputMethodManager_.class);
     if (apiLevel <= JELLY_BEAN_MR1) {
       _reflector.setMInstance(null);
-    } else if (apiLevel <= P) {
-      _reflector.setInstance(null);
     } else {
+      _reflector.setInstance(null);
+    }
+    if (apiLevel > P) {
       _reflector.getInstanceMap().clear();
     }
   }