Have content/ create and destroy its own threads.

content/test/test_browser_thread.cc

Index: content/test/test_browser_thread.cc
diff --git a/content/test/test_browser_thread.cc b/content/test/test_browser_thread.cc
index bd3191947a37015052b2b1920c60d5d116bd0077..9224726dcc8f231e7009240e2265b29f2b9caa84 100644
--- a/content/test/test_browser_thread.cc
+++ b/content/test/test_browser_thread.cc
@@ -10,13 +10,37 @@
 
 namespace content {
 
+// This gives access to set_message_loop().
+class TestBrowserThreadImpl : public BrowserThreadImpl {
+ public:
+  explicit TestBrowserThreadImpl(BrowserThread::ID identifier)
+      : BrowserThreadImpl(identifier) {
+  }
+
+  TestBrowserThreadImpl(BrowserThread::ID identifier,
+                        MessageLoop* message_loop)
+      : BrowserThreadImpl(identifier, message_loop) {
+  }
+
+  virtual ~TestBrowserThreadImpl() {
+    Stop();
+  }
+
+  void set_message_loop(MessageLoop* loop) {
+    Thread::set_message_loop(loop);
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestBrowserThreadImpl);
+};
+
 TestBrowserThread::TestBrowserThread(BrowserThread::ID identifier)
-    : impl_(new BrowserThreadImpl(identifier)) {
+    : impl_(new TestBrowserThreadImpl(identifier)) {
 }
 
 TestBrowserThread::TestBrowserThread(BrowserThread::ID identifier,
                                      MessageLoop* message_loop)
-    : impl_(new BrowserThreadImpl(identifier, message_loop)) {
+    : impl_(new TestBrowserThreadImpl(identifier, message_loop)) {
 }
 
 TestBrowserThread::~TestBrowserThread() {
@@ -45,4 +69,8 @@ base::Thread* TestBrowserThread::DeprecatedGetThreadObject() {
   return impl_.get();
 }
 
+void TestBrowserThread::DeprecatedSetMessageLoop(MessageLoop* loop) {
+  impl_->set_message_loop(loop);
+}
+
 }  // namespace content