[Gradle] Improve Android Studio support for javatests

This CL improves Android Studio support for javatests after
modularization. Since with the new clank structure, we are going to have
javatests and java files in one folder, we can list both of them in one
gradle target as well.

Bug: 620034
Change-Id: I48f6a376c87cb368ded662f868c1c1767755267e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2594770
Commit-Queue: Alice Wang <aliceywang@chromium.org>
Reviewed-by: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837989}

build/android/gradle/generate_gradle.py

@@ -578,13 +578,6 @@ def _GenerateGradleFile(entry, generator, build_vars, jinja_processor):
       _TemplatePath(target_type.split('_')[0]), variables)
 
 
-def _IsTestDir(path):
-  return ('javatests/' in path or
-          'junit/' in path or
-          'test/' in path or
-          'testing/' in path)
-
-
 # Example: //chrome/android:monochrome
 def _GetNative(relative_func, target_names):
   """Returns an object containing native c++ sources list and its included path
@@ -638,8 +631,11 @@ def _GenerateModuleAll(gradle_output_dir, generator, build_vars,
   res_dirs = sorted(generator.processed_res_dirs)
   def Relativize(paths):
     return _RebasePath(paths, os.path.join(gradle_output_dir, _MODULE_ALL))
-  main_java_dirs = [d for d in java_dirs if not _IsTestDir(d)]
-  test_java_dirs = [d for d in java_dirs if _IsTestDir(d)]
+
+  # As after clank modularization, the java and javatests code will live side by
+  # side in the same module, we will list both of them in the main target here.
+  main_java_dirs = [d for d in java_dirs if 'junit/' not in d]
+  junit_test_java_dirs = [d for d in java_dirs if 'junit/' in d]
   variables['main'] = {
       'android_manifest': Relativize(_DEFAULT_ANDROID_MANIFEST_PATH),
       'java_dirs': Relativize(main_java_dirs),
@@ -648,7 +644,7 @@ def _GenerateModuleAll(gradle_output_dir, generator, build_vars,
       'res_dirs': Relativize(res_dirs),
   }
   variables['android_test'] = [{
-      'java_dirs': Relativize(test_java_dirs),
+      'java_dirs': Relativize(junit_test_java_dirs),
       'java_excludes': ['**/*.java'],
   }]
   if native_targets: