Change CronetDataSource.buildRequestBuilder method to protected.

This allows overriding the implementation of building the UrlRequest
from dataSpec when necessary

PiperOrigin-RevId: 345149165

extensions/cronet/src/main/java/com/google/android/exoplayer2/ext/cronet/CronetDataSource.java

@@ -707,9 +707,7 @@ public class CronetDataSource extends BaseDataSource implements HttpDataSource {
     return responseInfo;
   }
 
-  // Internal methods.
-
-  private UrlRequest.Builder buildRequestBuilder(DataSpec dataSpec) throws IOException {
+  protected UrlRequest.Builder buildRequestBuilder(DataSpec dataSpec) throws IOException {
     UrlRequest.Builder requestBuilder =
         cronetEngine
             .newUrlRequestBuilder(dataSpec.uri.toString(), urlRequestCallback, executor)
@@ -759,6 +757,8 @@ public class CronetDataSource extends BaseDataSource implements HttpDataSource {
     return requestBuilder;
   }
 
+  // Internal methods.
+
   private boolean blockUntilConnectTimeout() throws InterruptedException {
     long now = clock.elapsedRealtime();
     boolean opened = false;