I'm synced to 6bd3f30a5dacfbed5a6d01232b4c2305e4c9960e and generate_gradle fails:

src$ build/android/gradle/generate_gradle.py --output-directory=out/Debug
W    0.000s Main  Creating project at: /usr/local/google/code/clankium2/src/out/Debug/gradle
ninja: Entering directory `/usr/local/google/code/clankium2/src/out/Debug'
ninja: no work to do.
W    8.023s Main  Building .build_config files...
ninja: Entering directory `/usr/local/google/code/clankium2/src/out/Debug'
ninja: no work to do.
Traceback (most recent call last):
  File "build/android/gradle/generate_gradle.py", line 894, in <module>
    main()
  File "build/android/gradle/generate_gradle.py", line 820, in main
    e.GetType() in ('android_apk', 'java_binary', 'junit_binary') or
  File "build/android/gradle/generate_gradle.py", line 225, in GetType
    return self.DepsInfo()['type']
  File "build/android/gradle/generate_gradle.py", line 215, in DepsInfo
    return self.BuildConfig()['deps_info']
  File "build/android/gradle/generate_gradle.py", line 211, in BuildConfig
    self._build_config = build_utils.ReadJson(_RebasePath(path))
  File "build/android/gradle/../gyp/util/build_utils.py", line 146, in ReadJson
    with open(path, 'r') as jsonfile:
IOError: [Errno 2] No such file or directory: '/usr/local/google/code/clankium2/src/out/Debug/gen/copy_cronet_java8_java_/cronet_api_java.build_config'

There is no such file, but there is /usr/local/google/code/clankium2/src/out/Debug/gen/components/cronet/android/copy_cronet_java8_java_:cronet_api_java.build_config

I suspect the issue is caused by crrev.com/c/960583, which added the following:

+    # _copy_target_name includes ${dep} which includes "_java", so in turn
+    # _copy_target_name contains "_java" which triggers
+    # build/config/android/internal_rules.gni whitelist of target names that
+    # must have build_configs, so emit one here.
+    write_build_config("${_copy_target_name}__build_config") {
+      build_config = "$target_gen_dir/$_copy_target_name.build_config"
+      type = "group"
+    }

Reverting that CL fixes the issue.