Selectively perform JNI registration in render processes on Android.

chrome/browser/android/chrome_entry_point.cc

 // Copyright 2015 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.
 
 #include "base/android/jni_android.h"
+#include "base/android/jni_utils.h"
 #include "base/android/library_loader/library_loader_hooks.h"
 #include "base/bind.h"
 #include "chrome/app/android/chrome_jni_onload.h"
 
 namespace {
 
 bool RegisterJNI(JNIEnv* env) {
   return true;
 }
 
 bool Init() {
   return true;
 }
 
 bool NativeInit() {
   return android::OnJNIOnLoadInit(base::Bind(&Init));
 }
 
 }  // namespace
 
 // This is called by the VM when the shared library is first loaded.
 JNI_EXPORT jint JNI_OnLoad(JavaVM* vm, void* reserved) {
+  // By default, all JNI methods are registered. However, since render processes
+  // don't need very much Java code, we enable selective JNI registration on the
+  // Java side and only register a subset of JNI methods.
+  base::android::InitVM(vm);
+  JNIEnv* env = base::android::AttachCurrentThread();
+  if (base::android::isSelectiveJniRegistrationEnabled(env)) {
+    base::android::SetJniRegistrationType(
+        base::android::SELECTIVE_JNI_REGISTRATION);
+  }
   if (!android::OnJNIOnLoadRegisterJNI(vm, base::Bind(&RegisterJNI))) {
     return -1;
   }
   base::android::SetNativeInitializationHook(NativeInit);
   return JNI_VERSION_1_4;
 }