Android: getting Cronet's Proguard setup ready for R8

Bug: 908988
Change-Id: I3f00b9e786d617fd288e90f2632bb86d18452502
Reviewed-on: https://chromium-review.googlesource.com/c/1358913Reviewed-by: Misha Efimov <mef@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Commit-Queue: Sam Maier <smaier@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613216}

components/cronet/android/BUILD.gn

@@ -992,6 +992,7 @@ if (!is_component_build) {
       "cronet_impl_common_proguard.cfg",
       "test/proguard.cfg",
       "//base/android/proguard/chromium_apk.flags",
+      "//testing/android/proguard_for_test.flags",
     ]
   }
 

components/cronet/android/test/proguard.cfg

 # Proguard configuration that is common for all type of tests.
 
--keepattributes Signature,InnerClasses,SourceFile,LineNumberTable
+-keepattributes Signature,InnerClasses,SourceFile,LineNumberTable,EnclosingMethod
 -dontwarn io.netty.**
 -keep class io.netty.** { *; }
 # Keep ChromiumNativeTestSupport & ChromiumPlatformOnlyTestSupport since they are

third_party/netty4/BUILD.gn

@@ -12,4 +12,5 @@ android_java_prebuilt("netty_all_java") {
   enable_bytecode_checks = false
   testonly = true
   jar_path = NETTY4_JAR_FILE
+  proguard_configs = [ "proguard.flags" ]
 }

third_party/netty4/proguard.flags

+# Netty4 references a number of classes that aren't included in the jar, and are
+# not found in third_party.
+-dontwarn org.jboss.marshalling.**
+-dontwarn org.eclipse.jetty.**
+-dontwarn com.sun.nio.sctp.**