Kapt3: Extract annotation processing to its own task in Gradle. Now the kotlinCompile task should know nothing about kapt, for the main task it's just a regular Java source root.

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinGradleSubplugin.kt

@@ -32,8 +32,13 @@ interface KotlinGradleSubplugin<KotlinCompile : AbstractCompile> {
             variantData: Any?,
             javaSourceSet: SourceSet?
     ): List<SubpluginOption>
-    
-    fun getPluginName(): String
+
+    fun getSubpluginKotlinTasks(
+            project: Project,
+            kotlinCompile: KotlinCompile
+    ): List<AbstractCompile> = emptyList()
+
+    fun getCompilerPluginId(): String
     fun getGroupName(): String
     fun getArtifactName(): String
 }