Revamping -keeps for @annotations

chrome/android/java/proguard.flags

 # Keep line number information, useful for stack traces.
 -keepattributes SourceFile,LineNumberTable
 
 # Keep the annotations.
 -keep @interface ***
 
 # Disable obfuscation for the following two packages.
 -keepnames class com.google.android.apps.chrome.**,org.chromium.** {
   *;
 }
 
 # Keep all the primitive and String constants for for the following two packages.
 -keepclassmembers class com.google.android.apps.chrome.**,org.chromium.** {
   !private static final % *;
   !private static final java.lang.String *;
 }
 
-# Keep code annotated with the following annotations.
--keep class com.google.android.apps.chrome.**,org.chromium.** {
+# Fragments are loaded using reflection via Fragment.instantiate(Context,String)
+# This can be improved upon - see b/622023.

[agrieve, 2016/06/22 18:08:06]

nit: Please use either crbug/622023, or http://crbug.com/622023.

b/ often refers to Google's bug tracker.

[smaier, 2016/06/22 18:24:06]

Done.

+-keep public class com.google.android.apps.chrome** extends android.app.Fragment
+-keep public class org.chromium** extends android.app.Fragment
+
+# This block will keep all members that are annotated to be kept.

[agrieve, 2016/06/22 18:08:06]

nit: this -> these, can you also elaborate to explain why this is different from
-keep. E.g.:
# Keep these class members if and only if the containing class is kept.

[smaier, 2016/06/22 18:24:06]

Discussed offline about these comments.

+-keepclasseswithmembers class com.google.android.apps.chrome.** {
   @**.AccessedByNative <fields>;
+}
+-keepclasseswithmembers class com.google.android.apps.chrome.** {
   @**.CalledByNative <methods>;
+}
+-keepclasseswithmembers class com.google.android.apps.chrome.** {
   @**.CalledByNativeUnchecked <methods>;
+}
+-keepclasseswithmembers class com.google.android.apps.chrome.** {
   @**.JavascriptInterface <methods>;
+}
+-keepclasseswithmembers class com.google.android.apps.chrome.** {
   @**.NativeCall <methods>;
+}
+-keepclasseswithmembers class com.google.android.apps.chrome.** {
   @**.UsedByReflection <methods>;
-  @**.VisibleForTesting *;
+}
+-keepclasseswithmembers class com.google.android.apps.chrome.** {
+  @**.VisibleForTesting <methods>;
+}
+-keepclasseswithmembers class com.google.android.apps.chrome.** {
   native <methods>;
 }
+-keepclasseswithmembers class org.chromium.** {
+  @**.AccessedByNative <fields>;
+}
+-keepclasseswithmembers class org.chromium.** {
+  @**.CalledByNative <methods>;

[agrieve, 2016/06/22 18:08:06]

I think we'd need a -keep for the ByNative ones as well?

+}
+-keepclasseswithmembers class org.chromium.** {
+  @**.CalledByNativeUnchecked <methods>;
+}
+-keepclasseswithmembers class org.chromium.** {
+  @**.JavascriptInterface <methods>;
+}
+-keepclasseswithmembers class org.chromium.** {
+  @**.NativeCall <methods>;
+}
+-keepclasseswithmembers class org.chromium.** {
+  @**.UsedByReflection <methods>;
+}
+-keepclasseswithmembers class org.chromium.** {
+  @**.VisibleForTesting <methods>;
+}
+-keepclasseswithmembers class org.chromium.** {
+  native <methods>;
+}
+
+# Keeping classes which are annotated to be kept
+-keep @**.UsedByReflection class *
+-keep @**.VisibleForTesting class *
+
 
 # Class merging provides negligible .dex size reduction and method count
 # reduction (about 0.3% improvement on method count, and 0.1% savings on size),
 # and it messes up stack traces if the classes are optimized. Thus, it is in our
 # best interests to turn it off. See crbug.com/620323
 -optimizations !class/merging/*
 
 # Keep all runtime visible annotations
 -keepattributes RuntimeVisibleAnnotations
 
@@ skipping 126 matching lines @@
   *;
 }
 
 # TODO(yfriedman): Remove when crbug.com/488192 is fixed.
 -dontwarn org.apache.http.conn.scheme.LayeredSocketFactory
 
 # Needed to run ChromeTest.apk
 -keepnames class com.google.android.gms.common.GoogleApiAvailability {
   *;
 }
+
+# Needed for chrome_sync_shell_test_apk. Note - these do no affect chrome_apk's
+# size.
+-keep class org.chromium.sync.protocol.* { *; }