Fix the crash when the SandboxedProcessService is destroyed through onDestroy.

content/app/android/sandboxed_process_service.cc

Index: content/app/android/sandboxed_process_service.cc
diff --git a/content/app/android/sandboxed_process_service.cc b/content/app/android/sandboxed_process_service.cc
index 556a6167bf4589dfeb9d69b6985a0b2e972a22dc..ea3db5578f68fb274c4cac276b2bf78cc04046e0 100644
--- a/content/app/android/sandboxed_process_service.cc
+++ b/content/app/android/sandboxed_process_service.cc
@@ -8,6 +8,8 @@
 #include "base/logging.h"
 #include "base/posix/global_descriptors.h"
 #include "content/common/android/surface_texture_peer.h"
+#include "content/common/child_process.h"
+#include "content/common/child_thread.h"
 #include "content/public/app/android_library_loader_hooks.h"
 #include "content/public/common/content_descriptors.h"
 #include "ipc/ipc_descriptors.h"
@@ -71,6 +73,10 @@ void InternalInitSandboxedProcess(const std::vector<int>& file_ids,
 
 }
 
+void QuitSandboxMainThreadMessageLoop() {
+  MessageLoop::current()->Quit();
+}
+
 }  // namespace <anonymous>
 
 namespace content {
@@ -100,4 +106,14 @@ bool RegisterSandboxedProcessService(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
+void ShutdownSandboxMainThread(JNIEnv* env, jobject obj) {
+  ChildProcess* current_process = ChildProcess::current();
+  if (!current_process)
+    return;
+  ChildThread* main_child_thread = current_process->main_thread();
+  if (main_child_thread && main_child_thread->message_loop())
+    main_child_thread->message_loop()->PostTask(FROM_HERE,
+        base::Bind(&QuitSandboxMainThreadMessageLoop));
+}
+
 }  // namespace content