Assign thread name to in_proc renderer and gpu thread.

content/renderer/in_process_renderer_thread.cc

Index: content/renderer/in_process_renderer_thread.cc
diff --git a/content/renderer/in_process_renderer_thread.cc b/content/renderer/in_process_renderer_thread.cc
index 8b4b333bb93580363a4f7bb5e7d693152856c69e..dea944faf21f98ca452eeefd9021cefa8424b8a4 100644
--- a/content/renderer/in_process_renderer_thread.cc
+++ b/content/renderer/in_process_renderer_thread.cc
@@ -8,6 +8,10 @@
 #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(
@@ -20,6 +24,13 @@ InProcessRendererThread::~InProcessRendererThread() {
 }
 
 void InProcessRendererThread::Init() {
+  // Call AttachCurrentThreadWithName, before any other AttachCurrentThread()
+  // calls, which 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());
+#endif
   render_process_.reset(new RenderProcessImpl());
   RenderThreadImpl::Create(params_);

[hush (inactive), 2015/12/12 00:09:32]

By the way, I'm sure AttachCurrentThread is called somewhere in line 34 or 35,
because the in_proc renderer thread (Android webview's blink thread) gets
assigned a Thread-??? by JVM, instead appearing as detached thread in
anr/traces.txt

[boliu, 2015/12/12 00:11:45]

At least video uses JNI on blink main thread. Also don't really matter either
way

 }