Pass file Regions along with FDs to child processes on Android

content/app/android/child_process_service.cc

 // Copyright (c) 2012 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 "content/app/android/child_process_service.h"
 
 #include <android/native_window_jni.h>
 #include <cpu-features.h>
 
 #include "base/android/jni_array.h"
@@ skipping 113 matching lines @@
 
  private:
   // The instance of org.chromium.content.app.ChildProcessService.
   base::android::ScopedJavaGlobalRef<jobject> service_;
 
   DISALLOW_COPY_AND_ASSIGN(SurfaceTextureManagerImpl);
 };
 
 // Chrome actually uses the renderer code path for all of its child
 // processes such as renderers, plugins, etc.
-void InternalInitChildProcess(const std::vector<int>& file_ids,
-                              const std::vector<int>& file_fds,
-                              JNIEnv* env,
+void InternalInitChildProcess(JNIEnv* env,
                               jclass clazz,
                               jobject context,
                               jobject service_in,
                               jint cpu_count,
                               jlong cpu_features) {
   base::android::ScopedJavaLocalRef<jobject> service(env, service_in);
 
   // Set the CPU properties.
   android_setCpu(cpu_count, cpu_features);
-  // Register the file descriptors.
-  // This includes the IPC channel, the crash dump signals and resource related
-  // files.
-  DCHECK(file_fds.size() == file_ids.size());
-  for (size_t i = 0; i < file_ids.size(); ++i)
-    base::GlobalDescriptors::GetInstance()->Set(file_ids[i], file_fds[i]);
-
   SurfaceTextureManager::SetInstance(new SurfaceTextureManagerImpl(service));
 
   base::android::MemoryPressureListenerAndroid::RegisterSystemCallback(env);
 }
 
 }  // namespace <anonymous>
 
+void RegisterGlobalFileDescriptor(JNIEnv* env,
+                                  jclass clazz,
+                                  jint id,
+                                  jint fd,
+                                  jlong offset,
+                                  jlong size) {
+  base::MemoryMappedFile::Region region(offset, size);
+  base::GlobalDescriptors::GetInstance()->Set(id, fd, region);
+}
+
 void InitChildProcess(JNIEnv* env,
                       jclass clazz,
                       jobject context,
                       jobject service,
-                      jintArray j_file_ids,
-                      jintArray j_file_fds,
                       jint cpu_count,
                       jlong cpu_features) {
-  std::vector<int> file_ids;
-  std::vector<int> file_fds;
-  JavaIntArrayToIntVector(env, j_file_ids, &file_ids);
-  JavaIntArrayToIntVector(env, j_file_fds, &file_fds);
-
-  InternalInitChildProcess(
-      file_ids, file_fds, env, clazz, context, service,
-      cpu_count, cpu_features);
+  InternalInitChildProcess(env, clazz, context, service, cpu_count,
+                           cpu_features);
 }
 
 void ExitChildProcess(JNIEnv* env, jclass clazz) {
   VLOG(0) << "ChildProcessService: Exiting child process.";
   base::android::LibraryLoaderExitHook();
   _exit(0);
 }
 
 bool RegisterChildProcessService(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 void ShutdownMainThread(JNIEnv* env, jobject obj) {
   ChildThreadImpl::ShutdownThread();
 }
 
 }  // namespace content