Don't allow proguard to rename Parcelables at all.

base/android/base_proguard_config.flags

 # Keep line number information, useful for stack traces.
 -keepattributes SourceFile,LineNumberTable
 
 # Keep all annotation related attributes that can affect runtime
 -keepattributes RuntimeVisible*Annotations
 -keepattributes AnnotationDefault
 
 # Keep the annotations, because if we don't, the ProGuard rules that use them
 # will not be respected. These classes then show up in our final dex, which we
 # do not want - see crbug.com/628226.
@@ skipping 20 matching lines @@
   @org.chromium.base.annotations.CalledByNativeUnchecked <methods>;
 }
 -keepclasseswithmembers class * {
   @org.chromium.base.annotations.UsedByReflection <methods>;
 }
 -keepclasseswithmembers,includedescriptorclasses class * {
   native <methods>;
 }
 
 # Keep all Parcelables as they might be marshalled outside Chrome.
+-keepnames class * implements android.os.Parcelable
+
 -keepclassmembers class * implements android.os.Parcelable {
   public static *** CREATOR;
 }
 
 # Remove methods annotated with this if their return value is unused
 -assumenosideeffects class ** {
   @org.chromium.base.annotations.RemovableInRelease <methods>;
 }
 
 # Keep all enum values and valueOf methods. See
 # http://proguard.sourceforge.net/index.html#manual/examples.html
 # for the reason for this. Also, see http://crbug.com/248037.
 -keepclassmembers enum * {
     public static **[] values();
 }