Try to diagnose blink reinitialisation in WebView.

content/renderer/in_process_renderer_thread.cc

 // Copyright 2013 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/renderer/in_process_renderer_thread.h"
 
+#include "base/command_line.h"
 #include "build/build_config.h"
+#include "content/public/common/content_switches.h"
 #include "content/renderer/render_process.h"
 #include "content/renderer/render_process_impl.h"
 #include "content/renderer/render_thread_impl.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/jni_android.h"
 #endif
 
 namespace content {
 
 InProcessRendererThread::InProcessRendererThread(
     const InProcessChildThreadParams& params)
     : Thread("Chrome_InProcRendererThread"), params_(params) {
 }
 
 InProcessRendererThread::~InProcessRendererThread() {
+#if defined(OS_ANDROID)
+  // Don't allow the render thread to be shut down in single process mode on
+  // Android. Temporary CHECK() to debug http://crbug.com/514141
+  CHECK(!base::CommandLine::ForCurrentProcess()->HasSwitch(

[johnme, 2016/04/19 14:25:10]

This check triggers frequently in content_browsertests:
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...

+      switches::kSingleProcess));
+#endif
+
   Stop();
 }
 
 void InProcessRendererThread::Init() {
   // Call AttachCurrentThreadWithName, before any other AttachCurrentThread()
   // calls. The latter causes Java VM to assign Thread-??? to the thread name.
   // Please note calls to AttachCurrentThreadWithName after AttachCurrentThread
   // will not change the thread name kept in Java VM.
 #if defined(OS_ANDROID)
   base::android::AttachCurrentThreadWithName(thread_name());
+  // Make sure we aren't somehow reinitialising the inprocess renderer thread on
+  // Android. Temporary CHECK() to debug http://crbug.com/514141
+  CHECK(!base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kSingleProcess) || !render_process_);
 #endif
   render_process_.reset(new RenderProcessImpl());
   RenderThreadImpl::Create(params_);
 }
 
 void InProcessRendererThread::CleanUp() {
+#if defined(OS_ANDROID)
+  // Don't allow the render thread to be shut down in single process mode on
+  // Android. Temporary CHECK() to debug http://crbug.com/514141
+  CHECK(!base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kSingleProcess));
+#endif
+
   render_process_.reset();
 
   // It's a little lame to manually set this flag.  But the single process
   // RendererThread will receive the WM_QUIT.  We don't need to assert on
   // this thread, so just force the flag manually.
   // If we want to avoid this, we could create the InProcRendererThread
   // directly with _beginthreadex() rather than using the Thread class.
   // We used to set this flag in the Init function above. However there
   // other threads like WebThread which are created by this thread
   // which resets this flag. Please see Thread::StartWithOptions. Setting
   // this flag to true in Cleanup works around these problems.
   SetThreadWasQuitProperly(true);
 }
 
 base::Thread* CreateInProcessRendererThread(
     const InProcessChildThreadParams& params) {
   return new InProcessRendererThread(params);
 }
 
 }  // namespace content