Have content/ create and destroy its own threads.

chrome/browser/chrome_browser_parts_views.h

Index: chrome/browser/chrome_browser_parts_views.h
diff --git a/chrome/browser/chrome_browser_parts_views.h b/chrome/browser/chrome_browser_parts_views.h
index e3805dc9acf49f5bafed783634d3a942cf1f2237..737640a5c5adeeee115b132ed1c8a1b6d156318d 100644
--- a/chrome/browser/chrome_browser_parts_views.h
+++ b/chrome/browser/chrome_browser_parts_views.h
@@ -10,6 +10,11 @@
 
 #include "base/compiler_specific.h"
 #include "content/public/browser/browser_main_parts.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace content {
+class IOThreadDelegate;
+}
 
 class ChromeBrowserPartsViews : public content::BrowserMainParts {
  public:
@@ -20,9 +25,13 @@ class ChromeBrowserPartsViews : public content::BrowserMainParts {
   virtual void PreMainMessageLoopStart() OVERRIDE {}
   virtual void ToolkitInitialized() OVERRIDE;
   virtual void PostMainMessageLoopStart() OVERRIDE {}
-  virtual void PreMainMessageLoopRun() OVERRIDE;
+  virtual content::IOThreadDelegate* PreMainMessageLoopRun() OVERRIDE;
+  virtual void PreMainMessageLoopRunThreadsCreated() OVERRIDE {}
   virtual bool MainMessageLoopRun(int* result_code) OVERRIDE;
   virtual void PostMainMessageLoopRun() OVERRIDE {}
+  virtual void PreStopThread(content::BrowserThread::ID identifier) OVERRIDE {}
+  virtual void PostStopThread(content::BrowserThread::ID identifier) OVERRIDE {}
+  virtual void FinalCleanup() OVERRIDE {}
 };
 
 #endif  // CHROME_BROWSER_CHROME_BROWSER_PARTS_VIEWS_H_