Add a -keep for all Parcelables in hopes it fixes crash in the wild

base/android/base_proguard_config.flags

Index: base/android/base_proguard_config.flags
diff --git a/base/android/base_proguard_config.flags b/base/android/base_proguard_config.flags
index f8b733d346ca196506d994dc9450796f5650b7b6..2775360d62a57b800c71c72b4c2026c74896cded 100644
--- a/base/android/base_proguard_config.flags
+++ b/base/android/base_proguard_config.flags
@@ -37,13 +37,20 @@
   native <methods>;
 }
 
-# Keep all Parcelables as they might be marshalled outside Chrome.
--keepnames class * implements android.os.Parcelable
-
+# Keep all CREATOR fields within Parcelable that are kept.
 -keepclassmembers class * implements android.os.Parcelable {
   public static *** CREATOR;
 }
 
+# Don't obfuscate Parcelables as they might be marshalled outside Chrome.
+-keepnames class * implements android.os.Parcelable
+
+# Keep all Parcelables, since Play Services has some that are used only by
+# reflection.
+# TODO(agrieve): Remove this once proguard flags provided by play services via
+#     .aars are used.  https://crbug.com/640836
+-keep class * implements android.os.Parcelable
+
 # Remove methods annotated with this if their return value is unused
 -assumenosideeffects class ** {
   @org.chromium.base.annotations.RemovableInRelease <methods>;