Have content/ create and destroy its own threads.

content/public/browser/browser_main_parts.h

Index: content/public/browser/browser_main_parts.h
diff --git a/content/public/browser/browser_main_parts.h b/content/public/browser/browser_main_parts.h
index 860541c4e14f6905585e9a2afc56634ca21983bc..4bce3cf45db7b6513c8f7710f030ef22732239c1 100644
--- a/content/public/browser/browser_main_parts.h
+++ b/content/public/browser/browser_main_parts.h
@@ -8,6 +8,7 @@
 
 #include "base/basictypes.h"
 #include "content/common/content_export.h"
+#include "content/public/browser/browser_thread.h"
 
 namespace content {
 
@@ -64,6 +65,24 @@ class CONTENT_EXPORT BrowserMainParts {
   // Allows an embedder to do any extra toolkit initialization.
   virtual void ToolkitInitialized() = 0;
 
+  // Called just before any child threads owned by the content
+  // framework are created.
+  //
+  // The main message loop has been started at this point (but has not
+  // been run), and the toolkit has been initialized.
+  virtual void PreCreateThreads() = 0;
+
+  // Called once for each thread owned by the content framework just
+  // before and just after the thread object is created and started.
+  // This happens in the order of the threads' appearence in the
+  // BrowserThread::ID enumeration.  Note that there will be no such
+  // call for BrowserThread::UI, since it is the main thread of the
+  // application.
+  virtual void PreStartThread(BrowserThread::ID identifier) = 0;
+  virtual void PostStartThread(BrowserThread::ID identifier) = 0;
+
+  // This is called just before the main message loop is run.  The
+  // various browser threads have all been created at this point
   virtual void PreMainMessageLoopRun() = 0;
 
   // Returns true if the message loop was run, false otherwise.
@@ -71,8 +90,22 @@ class CONTENT_EXPORT BrowserMainParts {
   // May set |result_code|, which will be returned by |BrowserMain()|.
   virtual bool MainMessageLoopRun(int* result_code) = 0;
 
+  // This happens after the main message loop has stopped, but before
+  // threads are stopped.
   virtual void PostMainMessageLoopRun() = 0;
 
+  // Called once for each thread owned by the content framework just
+  // before and just after it is torn down. This is in reverse order
+  // of the threads' appearance in the BrowserThread::ID enumeration.
+  // Note that you will not receive such a call for BrowserThread::UI,
+  // since it is the main thread of the application.
+  virtual void PreStopThread(BrowserThread::ID identifier) = 0;
+  virtual void PostStopThread(BrowserThread::ID identifier) = 0;
+
+  // Called as the very last part of shutdown, after threads have been
+  // stopped and destroyed.
+  virtual void PostDestroyThreads() = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(BrowserMainParts);
 };