Add more proguard rule workaround to make AppReduce happy.

Bug:1087646

Change-Id: If4e49aa2572ddc81c4487713368fbfb57689ae51
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2219603
Commit-Queue: Renjie Tang <renjietang@chromium.org>
Reviewed-by: Eric Roman <eroman@chromium.org>
Reviewed-by: Zhongyi Shi <zhongyi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773410}

components/cronet/android/BUILD.gn

@@ -482,6 +482,7 @@ action("cronet_combine_proguard_flags") {
 
     # Massage the proguard rules to work with AppReduce.
     "//components/cronet/android/cronet_appreduce_workaround.patch",
+    "//components/cronet/android/cronet_appreduce_workaround2.patch",
     "//components/cronet/android/cronet_impl_native_proguard.cfg",
   ]
   outputs = [ "$target_gen_dir/cronet_impl_native_proguard.cfg" ]

components/cronet/android/cronet_appreduce_workaround2.patch

+This patch works as a supplement for cronet_appreduce_workaround.patch.
+See crbug.com/1087646 on why this is needed.
+For more information, also see cronet_appreduce_workaround.patch.
+
+--- base/android/proguard/chromium_code.flags	2020-05-29 11:34:48.748109273 -0700
++++ modified.flags	2020-05-29 12:20:30.692111915 -0700
+@@ -34,13 +34,13 @@
+ -keep @org.chromium.base.annotations.UsedByReflection class ** {}
+ 
+ # Keeps for method level annotations.
+--keepclasseswithmembers,allowaccessmodification class ** {
++-keepclasseswithmembers class ** {
+   @org.chromium.base.annotations.AccessedByNative <fields>;
+ }
+--keepclasseswithmembers,includedescriptorclasses,allowaccessmodification class ** {
++-keepclasseswithmembers,includedescriptorclasses class ** {
+   @org.chromium.base.annotations.CalledByNative <methods>;
+ }
+--keepclasseswithmembers,includedescriptorclasses,allowaccessmodification class ** {
++-keepclasseswithmembers,includedescriptorclasses class ** {
+   @org.chromium.base.annotations.CalledByNativeUnchecked <methods>;
+ }
+ -keepclasseswithmembers class ** {