Replace reflection with direct calls to Android P APIs.

This is possible now that Android P SDK is in Chromium.
The direct calls are placed in an ApiHelper class to avoid ART runtime
verification issues.

Change-Id: I88cf7788006aaa63b708a16f52aad00132e28c05
Reviewed-on: https://chromium-review.googlesource.com/c/1335874Reviewed-by: Misha Efimov <mef@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Paul Jensen <pauljensen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608394}

base/BUILD.gn

@@ -2988,6 +2988,7 @@ if (is_android) {
       "android/java/src/org/chromium/base/compat/ApiHelperForM.java",
       "android/java/src/org/chromium/base/compat/ApiHelperForN.java",
       "android/java/src/org/chromium/base/compat/ApiHelperForO.java",
+      "android/java/src/org/chromium/base/compat/ApiHelperForP.java",
       "android/java/src/org/chromium/base/library_loader/LibraryLoader.java",
       "android/java/src/org/chromium/base/library_loader/Linker.java",
       "android/java/src/org/chromium/base/library_loader/LoaderErrors.java",

base/android/java/src/org/chromium/base/compat/ApiHelperForP.java

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.base.compat;
+
+import android.annotation.TargetApi;
+import android.net.LinkProperties;
+import android.os.Build;
+
+import org.chromium.base.annotations.DoNotInline;
+
+/**
+ * Utility class to use new APIs that were added in P (API level 28). These need to exist in a
+ * separate class so that Android framework can successfully verify classes without
+ * encountering the new APIs.
+ */
+@DoNotInline
+@TargetApi(Build.VERSION_CODES.P)
+public final class ApiHelperForP {
+    private ApiHelperForP() {}
+
+    /** See {@link LinkProperties#isPrivateDnsActive() }. */
+    public static boolean isPrivateDnsActive(LinkProperties linkProperties) {
+        return linkProperties.isPrivateDnsActive();
+    }
+
+    /** See {@link LinkProperties#getPrivateDnsServerName() }. */
+    public static String getPrivateDnsServerName(LinkProperties linkProperties) {
+        return linkProperties.getPrivateDnsServerName();
+    }
+}

net/android/java/src/org/chromium/net/AndroidNetworkLibrary.java

@@ -32,6 +32,7 @@ import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.CalledByNativeUnchecked;
 import org.chromium.base.annotations.MainDex;
 import org.chromium.base.compat.ApiHelperForM;
+import org.chromium.base.compat.ApiHelperForP;
 import org.chromium.base.metrics.RecordHistogram;
 
 import java.io.FileDescriptor;
@@ -64,10 +65,6 @@ import java.util.Set;
 class AndroidNetworkLibrary {
     private static final String TAG = "AndroidNetworkLibrary";
 
-    // Cached Method for LinkProperties.isPrivateDnsActive().
-    private static Method sIsPrivateDnsActiveMethod;
-    // Cached Method for LinkProperties.getPrivateDnsServerName().
-    private static Method sGetPrivateDnsServerNameMethod;
     // Cached value indicating if app has ACCESS_NETWORK_STATE permission.
     private static Boolean sHaveAccessNetworkState;
 
@@ -342,18 +339,7 @@ class AndroidNetworkLibrary {
      */
     static boolean isPrivateDnsActive(LinkProperties linkProperties) {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P && linkProperties != null) {
-            // TODO(pauljensen): When Android P SDK is available, remove reflection.
-            try {
-                // This could be racy if called on multiple threads, but races will
-                // end in the same result so it's not a problem.
-                if (sIsPrivateDnsActiveMethod == null) {
-                    sIsPrivateDnsActiveMethod =
-                            linkProperties.getClass().getMethod("isPrivateDnsActive");
-                }
-                return ((Boolean) sIsPrivateDnsActiveMethod.invoke(linkProperties)).booleanValue();
-            } catch (Exception e) {
-                Log.e(TAG, "Can not call LinkProperties.isPrivateDnsActive():", e);
-            }
+            return ApiHelperForP.isPrivateDnsActive(linkProperties);
         }
         return false;
     }
@@ -363,18 +349,7 @@ class AndroidNetworkLibrary {
      */
     private static String getPrivateDnsServerName(LinkProperties linkProperties) {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P && linkProperties != null) {
-            // TODO(pauljensen): When Android P SDK is available, remove reflection.
-            try {
-                // This could be racy if called on multiple threads, but races will
-                // end in the same result so it's not a problem.
-                if (sGetPrivateDnsServerNameMethod == null) {
-                    sGetPrivateDnsServerNameMethod =
-                            linkProperties.getClass().getMethod("getPrivateDnsServerName");
-                }
-                return (String) sGetPrivateDnsServerNameMethod.invoke(linkProperties);
-            } catch (Exception e) {
-                Log.e(TAG, "Can not call LinkProperties.getPrivateDnsServerName():", e);
-            }
+            return ApiHelperForP.getPrivateDnsServerName(linkProperties);
         }
         return null;
     }