Make base::MessageLoops have names at construction time

base/message_loop.h

Index: base/message_loop.h
diff --git a/base/message_loop.h b/base/message_loop.h
index 9d500d7dd898a0e8e344328b310352823f8c6392..df349c8a7d6f67ef4299c558f3ecdca2961c325a 100644
--- a/base/message_loop.h
+++ b/base/message_loop.h
@@ -107,7 +107,8 @@ class BASE_API MessageLoop : public base::MessagePump::Delegate {
 
   // Normally, it is not necessary to instantiate a MessageLoop.  Instead, it
   // is typical to make use of the current thread's MessageLoop instance.
-  explicit MessageLoop(Type type = TYPE_DEFAULT);
+  explicit MessageLoop(Type type = TYPE_DEFAULT,
+                       const char* thread_name = NULL);
   virtual ~MessageLoop();
 
   // Returns the MessageLoop object for the current thread, or null if none.
@@ -255,11 +256,7 @@ class BASE_API MessageLoop : public base::MessagePump::Delegate {
   // Returns the type passed to the constructor.
   Type type() const { return type_; }
 
-  // Optional call to connect the thread name with this loop.
-  void set_thread_name(const std::string& thread_name) {
-    DCHECK(thread_name_.empty()) << "Should not rename this thread!";
-    thread_name_ = thread_name;
-  }
+  // Returns the name associated with this message loop's thread.
   const std::string& thread_name() const { return thread_name_; }
 
   // Enables or disables the recursive task processing. This happens in the case
@@ -569,7 +566,8 @@ class BASE_API MessageLoop : public base::MessagePump::Delegate {
 //
 class BASE_API MessageLoopForUI : public MessageLoop {
  public:
-  MessageLoopForUI() : MessageLoop(TYPE_UI) {
+  MessageLoopForUI(const char* thread_name)
+      : MessageLoop(thread_name, TYPE_UI) {
   }
 
   // Returns the MessageLoopForUI of the current thread.
@@ -631,7 +629,8 @@ class BASE_API MessageLoopForIO : public MessageLoop {
 
 #endif
 
-  MessageLoopForIO() : MessageLoop(TYPE_IO) {
+  MessageLoopForIO(const char* thread_name)
+      : MessageLoop(thread_name, TYPE_IO) {
   }
 
   // Returns the MessageLoopForIO of the current thread.