Docs: clarify WebView support for cleartext traffic

No change to logic, docs change only.

WebView added support for android:usesCleartextTraffic for apps
targeting O and above (API level 26). This CL clarifies WebView's
support in the Android documentation.

This also fixes a preexisting presubmit error in
NetworkSecurityPolicy.java (unused import).

Bug: 67714197
Test: N/A
Change-Id: If6bfd36bc65926a1b032813598c85146ccfde969
diff --git a/core/java/android/content/pm/ApplicationInfo.java b/core/java/android/content/pm/ApplicationInfo.java
index d73f852..dcc6821 100644
--- a/core/java/android/content/pm/ApplicationInfo.java
+++ b/core/java/android/content/pm/ApplicationInfo.java
@@ -375,7 +375,7 @@
      * {@code DownloadManager}, {@code MediaPlayer}) will refuse app's requests to use cleartext
      * traffic. Third-party libraries are encouraged to honor this flag as well.
      *
-     * <p>NOTE: {@code WebView} does not honor this flag.
+     * <p>NOTE: {@code WebView} honors this flag for applications targeting API level 26 and up.
      *
      * <p>This flag is ignored on Android N and above if an Android Network Security Config is
      * present.
diff --git a/core/java/android/security/NetworkSecurityPolicy.java b/core/java/android/security/NetworkSecurityPolicy.java
index 812c956..0c4eeda 100644
--- a/core/java/android/security/NetworkSecurityPolicy.java
+++ b/core/java/android/security/NetworkSecurityPolicy.java
@@ -16,7 +16,6 @@
 
 package android.security;
 
-import android.annotation.TestApi;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.security.net.config.ApplicationConfig;
@@ -63,7 +62,8 @@
      * traffic from applications is handled by higher-level network stacks/components which can
      * honor this aspect of the policy.
      *
-     * <p>NOTE: {@link android.webkit.WebView} does not honor this flag.
+     * <p>NOTE: {@link android.webkit.WebView} honors this flag for applications targeting API level
+     * 26 and up.
      */
     public boolean isCleartextTrafficPermitted() {
         return libcore.net.NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted();