R8 specific rules to allow for service loader optimizations (#2880)

Fixes the R8 ServiceLoader optimization that broke in the R8
bundled in the new AGP. For details, see
https://issuetracker.google.com/issues/196302685

kotlinx-coroutines-core/jvm/resources/META-INF/com.android.tools/proguard/coroutines.pro

@@ -0,0 +1,24 @@
+# When editing this file, update the following files as well:
+# - META-INF/proguard/coroutines.pro
+# - META-INF/com.android.tools/r8/coroutines.pro
+
+# ServiceLoader support
+-keepnames class kotlinx.coroutines.internal.MainDispatcherFactory {}
+-keepnames class kotlinx.coroutines.CoroutineExceptionHandler {}
+
+# Most of volatile fields are updated with AFU and should not be mangled
+-keepclassmembers class kotlinx.coroutines.** {
+    volatile <fields>;
+}
+
+# Same story for the standard library's SafeContinuation that also uses AtomicReferenceFieldUpdater
+-keepclassmembers class kotlin.coroutines.SafeContinuation {
+    volatile <fields>;
+}
+
+# These classes are only required by kotlinx.coroutines.debug.AgentPremain, which is only loaded when
+# kotlinx-coroutines-core is used as a Java agent, so these are not needed in contexts where ProGuard is used.
+-dontwarn java.lang.instrument.ClassFileTransformer
+-dontwarn sun.misc.SignalHandler
+-dontwarn java.lang.instrument.Instrumentation
+-dontwarn sun.misc.Signal

kotlinx-coroutines-core/jvm/resources/META-INF/com.android.tools/r8/coroutines.pro

@@ -0,0 +1,20 @@
+# When editing this file, update the following files as well:
+# - META-INF/proguard/coroutines.pro
+# - META-INF/com.android.tools/proguard/coroutines.pro
+
+# Most of volatile fields are updated with AFU and should not be mangled
+-keepclassmembers class kotlinx.coroutines.** {
+    volatile <fields>;
+}
+
+# Same story for the standard library's SafeContinuation that also uses AtomicReferenceFieldUpdater
+-keepclassmembers class kotlin.coroutines.SafeContinuation {
+    volatile <fields>;
+}
+
+# These classes are only required by kotlinx.coroutines.debug.AgentPremain, which is only loaded when
+# kotlinx-coroutines-core is used as a Java agent, so these are not needed in contexts where ProGuard is used.
+-dontwarn java.lang.instrument.ClassFileTransformer
+-dontwarn sun.misc.SignalHandler
+-dontwarn java.lang.instrument.Instrumentation
+-dontwarn sun.misc.Signal

kotlinx-coroutines-core/jvm/resources/META-INF/proguard/coroutines.pro

@@ -1,3 +1,7 @@
+# When editing this file, update the following files as well:
+# - META-INF/com.android.tools/proguard/coroutines.pro
+# - META-INF/com.android.tools/r8/coroutines.pro
+
 # ServiceLoader support
 -keepnames class kotlinx.coroutines.internal.MainDispatcherFactory {}
 -keepnames class kotlinx.coroutines.CoroutineExceptionHandler {}