Start removing flag for rclass generator (make nop)

Flip option default to true to mirror flag flip
and make the option a nop. After that we can remove
the flag reference, and then we can remove
the actual option.

RELNOTES: --{no}experimental_use_rclass_generator
is now a nop. It's been on by default for a while,
and there are no references, so seems safe to remove.

--
MOS_MIGRATED_REVID=140602921
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidCommon.java b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidCommon.java
index 2105496..31ac2be 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidCommon.java
@@ -563,9 +563,7 @@
       // Use a fast-path R class generator for android_binary with local resources, where there is
       // a bottleneck. For legacy resources, the srcjar and R class compiler don't match up
       // (the legacy srcjar requires the createJarJar step below).
-      boolean useRClassGenerator =
-          getAndroidConfig(ruleContext).useRClassGenerator()
-          && isBinary && !resourceApk.isLegacy();
+      boolean useRClassGenerator = isBinary && !resourceApk.isLegacy();
       compileResources(javaSemantics, resourceApk, resourcesJar, artifactsBuilder, attributes,
           filesBuilder, jarsProducedForRuntime, useRClassGenerator);
       if (resourceApk.isLegacy()) {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidConfiguration.java
index cab35ff..561b1cf 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidConfiguration.java
@@ -373,8 +373,9 @@
     // Do not use on the command line.
     // The idea is that once this option works, we'll flip the default value in a config file, then
     // once it is proven that it works, remove it from Bazel and said config file.
+    // This is now on by default and the flag is a noop and will be removed in a future release.
     @Option(name = "experimental_use_rclass_generator",
-        defaultValue = "false",
+        defaultValue = "true",
         category = "undocumented",
         help = "Use the specialized R class generator to build the final app and lib R classes.")
     public boolean useRClassGenerator;
@@ -480,7 +481,6 @@
   private final boolean useRexToCompressDexFiles;
   private final boolean allowAndroidLibraryDepsWithoutSrcs;
   private final boolean useAndroidResourceShrinking;
-  private final boolean useRClassGenerator;
   private final boolean useParallelResourceProcessing;
   private final AndroidManifestMerger manifestMerger;
   private final ApkSigningMethod apkSigningMethod;
@@ -506,7 +506,6 @@
     this.desugarJava8 = options.desugarJava8;
     this.allowAndroidLibraryDepsWithoutSrcs = options.allowAndroidLibraryDepsWithoutSrcs;
     this.useAndroidResourceShrinking = options.useAndroidResourceShrinking;
-    this.useRClassGenerator = options.useRClassGenerator;
     this.useParallelResourceProcessing = options.useParallelResourceProcessing;
     this.manifestMerger = options.manifestMerger;
     this.apkSigningMethod = options.apkSigningMethod;
@@ -581,10 +580,6 @@
     return useAndroidResourceShrinking;
   }
 
-  public boolean useRClassGenerator() {
-    return useRClassGenerator;
-  }
-
   public boolean useParallelResourceProcessing() {
     return useParallelResourceProcessing;
   }