Add API for custom library loading

components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java

Index: components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java
diff --git a/components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java b/components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java
index ce07d6bdca5eb22145ced74721f3991f8d7bd926..2d8d1ce726e9852f5461578e04a6e9e1ee3436de 100644
--- a/components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java
+++ b/components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java
@@ -960,4 +960,46 @@ public class CronetUrlRequestContextTest extends CronetTestBase {
     // Verifies that CronetEngine.Builder config from testCronetEngineBuilderConfig() is properly
     // translated to a native UrlRequestContextConfig.
     private static native void nativeVerifyUrlRequestContextConfig(long config, String storagePath);
+
+    private static class TestBadLibraryLoader implements CronetEngine.Builder.CustomLibraryLoader {
+        public void loadLibrary(String libName) {
+            // Don't do anything
+        }
+    }
+
+    @SmallTest
+    @Feature({"Cronet"})
+    public void testSkipLibraryLoading() throws Exception {
+        CronetEngine.Builder builder = new CronetEngine.Builder(getContext());
+        builder.setLibraryLoader(new TestBadLibraryLoader()).setLibraryName("cronet_tests");
+        try {
+            // ensureInitialized() calls native code to check the version right after library load
+            // and will error with the message below if library loading was skipped
+            CronetLibraryLoader.ensureInitialized(getContext(), builder);
+            fail("Native library should not be loaded");
+        } catch (UnsatisfiedLinkError e) {
+            assertTrue(e.getMessage().contains(
+                    "No implementation found for java.lang.String org.chromium.net"));
+        }
+    }
+
+    private static class TestCustomLibraryLoader
+            implements CronetEngine.Builder.CustomLibraryLoader {
+        public void loadLibrary(String libName) {
+            // Ignore the given name, always load the test library
+            System.loadLibrary("cronet_tests");
+        }
+    }
+
+    @SmallTest
+    @Feature({"Cronet"})
+    public void testOverrideLibraryLoading() throws Exception {
+        CronetEngine.Builder builder = new CronetEngine.Builder(getContext());
+        // Don't tell the builder directly that it needs to load the test library
+        // Instead, let the custom library loader do that
+        builder.setLibraryLoader(new TestCustomLibraryLoader()).build();
+        nativeLibraryExists();
+    }
+
+    private static native void nativeLibraryExists();
 }