[Cronet] Add proguard files for different Cronet packaging

components/cronet/android/cronet_impl_native_proguard.cfg

Index: components/cronet/android/cronet_impl_native_proguard.cfg
diff --git a/components/cronet/android/proguard.cfg b/components/cronet/android/cronet_impl_native_proguard.cfg
similarity index 78%
rename from components/cronet/android/proguard.cfg
rename to components/cronet/android/cronet_impl_native_proguard.cfg
index 1d6c8e1728b108ab14a808605c79343fb8976953..9ee247f299843b98c31948c5d1b7e4fec0366c7d 100644
--- a/components/cronet/android/proguard.cfg
+++ b/components/cronet/android/cronet_impl_native_proguard.cfg
@@ -1,13 +1,8 @@
+# Proguard config for apps that depend on cronet_impl_native_java.jar.
+
 -keep class org.chromium.net.impl.CronetUrlRequest$HeadersList
 -keep class org.chromium.net.impl.ChromiumUrlRequest$ResponseHeadersMap
 
-# This constructor is called by the reflection from Cronet API. It cannot be
-# annotated with @org.chromium.base.annotations.AccessedByNative in order to
-# avoid the dependency on Chromium-Base Java classes.
--keep class org.chromium.net.impl.CronetEngineBuilderImpl {
-    public <init>(android.content.Context);
-}
-
 # Suppress unnecessary warnings.
 -dontnote org.chromium.net.ProxyChangeListener$ProxyReceiver
 -dontnote org.chromium.net.AndroidKeyStore