Enable emma code coverage for JUnit testcases.

build/config/android/internal_rules.gni

Index: build/config/android/internal_rules.gni
diff --git a/build/config/android/internal_rules.gni b/build/config/android/internal_rules.gni
index a11f4a04239c353b7a930115bf92955a19bbcfc7..d0584bd7b50ace14516a73e5f9761217cfa3ee1b 100644
--- a/build/config/android/internal_rules.gni
+++ b/build/config/android/internal_rules.gni
@@ -240,6 +240,15 @@ template("java_binary_script") {
       "--main-class",
       _main_class,
     ]
+    if (emma_coverage) {
+      args += [
+        "--classpath",
+        rebase_path(
+            "//third_party/android_tools_internal/sdk/tools/lib/emma.jar",
+            root_build_dir),
+      ]
+      args += [ "--noverify" ]
+    }
     if (defined(invoker.wrapper_script_args)) {
       args += [ "--" ] + invoker.wrapper_script_args
     }