JNI refactor: @NativeMethods conversion (VariationsSession).

This CL was partially created by
//base/android/jni_generator/jni_refactorer.py.

The conversion also required converting unit tests to use the new JNI
mocking approach provided by JniMocker.

Also removed a couple of unused methods.

Bug: 929661
Change-Id: Ic34608693e7c48313512c8ef7e48943023de2af5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1833078Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Eric Stevenson <estevenson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702035}

chrome/android/java/src/org/chromium/chrome/browser/metrics/VariationsSession.java

@@ -4,9 +4,8 @@
 
 package org.chromium.chrome.browser.metrics;
 
-import android.content.Context;
-
 import org.chromium.base.Callback;
+import org.chromium.base.annotations.NativeMethods;
 
 /**
  * Sets up communication with the VariationsService. This is primarily used for
@@ -20,14 +19,9 @@ public class VariationsSession {
      * Triggers to the native VariationsService that the application has entered the foreground.
      */
     public void start() {
-        start(null);
-    }
-
-    // TODO(agrieve): Delete after updating downstream.
-    public void start(Context unused) {
         // If |mRestrictModeFetchStarted| is true and |mRestrictMode| is null, then async
-        // initializationn is in progress and nativeStartVariationsSession() will be called
-        // when it completes.
+        // initialization is in progress and VariationsSessionJni.get().startVariationsSession()
+        // will be called when it completes.
         if (mRestrictModeFetchStarted && mRestrictMode == null) {
             return;
         }
@@ -36,7 +30,8 @@ public class VariationsSession {
         getRestrictModeValue(new Callback<String>() {
             @Override
             public void onResult(String restrictMode) {
-                nativeStartVariationsSession(mRestrictMode);
+                VariationsSessionJni.get().startVariationsSession(
+                        VariationsSession.this, mRestrictMode);
             }
         });
     }
@@ -71,11 +66,6 @@ public class VariationsSession {
      * restrict values, which must not be null.
      */
     protected void getRestrictMode(Callback<String> callback) {
-        // TODO(agrieve): Refactor downstream.
-        getRestrictMode(null, callback);
-    }
-
-    protected void getRestrictMode(Context unused, Callback<String> callback) {
         callback.onResult("");
     }
 
@@ -83,9 +73,12 @@ public class VariationsSession {
      * @return The latest country according to the current variations state. Null if not known.
      */
     public String getLatestCountry() {
-        return nativeGetLatestCountry();
+        return VariationsSessionJni.get().getLatestCountry(this);
     }
 
-    protected native void nativeStartVariationsSession(String restrictMode);
-    protected native String nativeGetLatestCountry();
+    @NativeMethods
+    interface Natives {
+        void startVariationsSession(VariationsSession caller, String restrictMode);
+        String getLatestCountry(VariationsSession caller);
+    }
 }

chrome/android/junit/src/org/chromium/chrome/browser/metrics/VariationsSessionTest.java

@@ -4,19 +4,23 @@
 
 package org.chromium.chrome.browser.metrics;
 
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.never;
-import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
 import org.robolectric.annotation.Config;
 
 import org.chromium.base.Callback;
 import org.chromium.base.test.BaseRobolectricTestRunner;
+import org.chromium.base.test.util.JniMocker;
 
 /**
  * Tests for VariationsSession
@@ -24,6 +28,11 @@ import org.chromium.base.test.BaseRobolectricTestRunner;
 @RunWith(BaseRobolectricTestRunner.class)
 @Config(manifest = Config.NONE)
 public class VariationsSessionTest {
+    @Rule
+    public JniMocker mocker = new JniMocker();
+    @Mock
+    private VariationsSession.Natives mVariationsSessionJniMock;
+
     private TestVariationsSession mSession;
 
     private static class TestVariationsSession extends VariationsSession {
@@ -37,26 +46,24 @@ public class VariationsSessionTest {
         public void runCallback(String value) {
             mCallback.onResult(value);
         }
-
-        @Override
-        protected void nativeStartVariationsSession(String restrictMode) {
-            // No-op for tests.
-        }
     }
 
     @Before
     public void setUp() {
-        mSession = spy(new TestVariationsSession());
+        MockitoAnnotations.initMocks(this);
+        mocker.mock(VariationsSessionJni.TEST_HOOKS, mVariationsSessionJniMock);
+        mSession = new TestVariationsSession();
     }
 
     @Test
     public void testStart() {
         mSession.start();
-        verify(mSession, never()).nativeStartVariationsSession(any(String.class));
+        verify(mVariationsSessionJniMock, never())
+                .startVariationsSession(eq(mSession), any(String.class));
 
         String restrictValue = "test";
         mSession.runCallback(restrictValue);
-        verify(mSession, times(1)).nativeStartVariationsSession(restrictValue);
+        verify(mVariationsSessionJniMock, times(1)).startVariationsSession(mSession, restrictValue);
     }
 
     @Test
@@ -67,9 +74,10 @@ public class VariationsSessionTest {
         });
         String restrictValue = "test";
         mSession.runCallback(restrictValue);
-        verify(mSession, never()).nativeStartVariationsSession(any(String.class));
+        verify(mVariationsSessionJniMock, never())
+                .startVariationsSession(eq(mSession), any(String.class));
 
         mSession.start();
-        verify(mSession, times(1)).nativeStartVariationsSession(restrictValue);
+        verify(mVariationsSessionJniMock, times(1)).startVariationsSession(mSession, restrictValue);
     }
 }