Selectively perform JNI registration in render processes on Android.

base/android/jni_generator/jni_generator_helper.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_ANDROID_JNI_GENERATOR_JNI_GENERATOR_HELPER_H_
 #define BASE_ANDROID_JNI_GENERATOR_JNI_GENERATOR_HELPER_H_
 
 #include <jni.h>
 
 #include "base/android/jni_android.h"
+#include "base/android/library_loader/library_loader_hooks.h"
 #include "base/android/scoped_java_ref.h"
 #include "base/logging.h"
 #include "build/build_config.h"
 
 // Project-specific macros used by the header files generated by
 // jni_generator.py. Different projects can then specify their own
 // implementation for this file.
 #define CHECK_NATIVE_PTR(env, jcaller, native_ptr, method_name, ...) \
   DCHECK(native_ptr) << method_name;
 
@@ skipping 14 matching lines @@
 inline void HandleRegistrationError(JNIEnv* env,
                                     jclass clazz,
                                     const char* filename) {
   LOG(ERROR) << "RegisterNatives failed in " << filename;
 }
 
 inline void CheckException(JNIEnv* env) {
   base::android::CheckException(env);
 }
 
+inline bool ShouldSkipJniRegistration(bool is_maindex_class) {
+  base::android::JniRegistrationType jni_type =
+      base::android::GetJniRegistrationType();
+  if (jni_type == base::android::NO_JNI_REGISTRATION) {
+    // TODO(estevenson): Change this to a DCHECK.
+    return true;
+  } else if (jni_type == base::android::ALL_JNI_REGISTRATION) {
+    return false;
+  } else if (jni_type == base::android::SELECTIVE_JNI_REGISTRATION) {
+    return !is_maindex_class;
+  } else {
+    // The registration type isn't always initialized in tests by this point.

[estevenson, 2017/01/09 13:20:00]

Not sure about this. In instrumentation tests the LibraryProcessType is often
PROCESS_UNINITIALIZED. Is there an error case where we might see a
PROCESS_UNINITIALIZED and assuming we're in a test and registering everything
would be incorrect? 

If so, we don't currently seem to handle that case - so is this an okay
temporary
solution until LibraryProcessType is removed from native?

[Torne, 2017/01/09 16:43:32]

I don't think it's okay that we ever see PROCESS_UNINITIALIZED :/
I'm not sure how that could even be happening; it's set by LibraryLoader.

[estevenson, 2017/01/12 03:46:49]

Added init code everywhere necessary for tests.

+    return false;
+  }
+}
+
 }  // namespace jni_generator
 
 #endif  // BASE_ANDROID_JNI_GENERATOR_JNI_GENERATOR_HELPER_H_