Revert of Add API for custom library loading (patchset #5 id:80001 of...

Revert of Add API for custom library loading (patchset #5 id:80001 of https://codereview.chromium.org/1619673004/ )

Reason for revert:
New test (CronetUrlRequestContextTest#testSkipLibraryLoading) fails on bots

BUG=581309

Original issue's description:
> Add API for custom library loading
>
> Loading the native library can cause a crash on some older versions of
> Android. This CL provides a way for embedders to implement custom library
> loading logic that works around the issue.
>
> BUG=550584
> R=xunjieli@chromium.org
>
> Committed: https://crrev.com/12d01cb35ec0ed7a259c19dd1390b5a486d61a9d
> Cr-Commit-Position: refs/heads/master@{#371319}

TBR=xunjieli@chromium.org,mgersh@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=550584

Review URL: https://codereview.chromium.org/1635033002

Cr-Commit-Position: refs/heads/master@{#371489}

components/cronet/android/api/src/org/chromium/net/CronetEngine.java

@@ -41,21 +41,6 @@ public abstract class CronetEngine {
      * then {@link #build} is called to create the {@code CronetEngine}.
      */
     public static class Builder {
-        /**
-         * A class which provides a method for loading the cronet native library. Apps needing to
-         * implement custom library loading logic can inherit from this class and pass an instance
-         * to {@link CronetEngine.Builder#setLibraryLoader}. For example, this might be required
-         * to work around {@code UnsatisfiedLinkError}s caused by flaky installation on certain
-         * older devices.
-         */
-        public abstract static class LibraryLoader {
-            /**
-             * Loads the native library.
-             * @param libName name of the library to load
-             */
-            public abstract void loadLibrary(String libName);
-        }
-
         // A hint that a host supports QUIC.
         static class QuicHint {
             // The host.
@@ -101,7 +86,6 @@ public abstract class CronetEngine {
         private String mUserAgent;
         private String mStoragePath;
         private boolean mLegacyModeEnabled;
-        private LibraryLoader mLibraryLoader;
         private String mLibraryName;
         private boolean mQuicEnabled;
         private boolean mHttp2Enabled;
@@ -203,22 +187,8 @@ public abstract class CronetEngine {
             return this;
         }
 
-        /**
-         * Sets a {@link LibraryLoader} to be used to load the native library.
-         * If not set, the library will be loaded using {@link System#loadLibrary}.
-         * @return the builder to facilitate chaining.
-         */
-        public Builder setLibraryLoader(LibraryLoader loader) {
-            mLibraryLoader = loader;
-            return this;
-        }
-
-        void loadLibrary() {
-            if (mLibraryLoader == null) {
-                System.loadLibrary(mLibraryName);
-            } else {
-                mLibraryLoader.loadLibrary(mLibraryName);
-            }
+        String libraryName() {
+            return mLibraryName;
         }
 
         /**

components/cronet/android/java/src/org/chromium/net/CronetLibraryLoader.java

@@ -32,7 +32,7 @@ class CronetLibraryLoader {
             if (sInitTaskPosted) {
                 return;
             }
-            builder.loadLibrary();
+            System.loadLibrary(builder.libraryName());
             if (!Version.CRONET_VERSION.equals(nativeGetCronetVersion())) {
                 throw new RuntimeException(String.format(
                       "Expected Cronet version number %s, "
@@ -74,7 +74,7 @@ class CronetLibraryLoader {
         nativeCronetInitOnMainThread();
     }
 
-    // Native methods are implemented in cronet_library_loader.cc.
+    // Native methods are implemented in cronet_loader.cc.
     private static native void nativeCronetInitOnMainThread();
     private static native String nativeGetCronetVersion();
 }

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

@@ -960,35 +960,4 @@ 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 extends CronetEngine.Builder.LibraryLoader {
-        private boolean mWasCalled = false;
-
-        public void loadLibrary(String libName) {
-            // Report that this method was called, but don't load the library
-            mWasCalled = true;
-        }
-
-        boolean wasCalled() {
-            return mWasCalled;
-        }
-    }
-
-    @SmallTest
-    @Feature({"Cronet"})
-    public void testSkipLibraryLoading() throws Exception {
-        CronetEngine.Builder builder = new CronetEngine.Builder(getContext());
-        TestBadLibraryLoader loader = new TestBadLibraryLoader();
-        builder.setLibraryLoader(loader).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"));
-            assertTrue(loader.wasCalled());
-        }
-    }
 }