Have content/ create and destroy its own threads.

chrome/browser/chrome_browser_parts_touch.h

Index: chrome/browser/chrome_browser_parts_touch.h
diff --git a/chrome/browser/chrome_browser_parts_touch.h b/chrome/browser/chrome_browser_parts_touch.h
index 0cd9502f6e4dabf89d49ad35d8aa255c8e64939e..3ccc8d93bea3a221292c2ba470a88d88aa3639b4 100644
--- a/chrome/browser/chrome_browser_parts_touch.h
+++ b/chrome/browser/chrome_browser_parts_touch.h
@@ -9,6 +9,10 @@
 #include "base/compiler_specific.h"
 #include "content/public/browser/browser_main_parts.h"
 
+namespace content {
+class IOThreadDelegate;
+}
+
 class ChromeBrowserPartsTouch : public content::BrowserMainParts {
  public:
   ChromeBrowserPartsTouch();
@@ -18,9 +22,13 @@ class ChromeBrowserPartsTouch : 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) OVERRIDE {}
+  virtual void PostStopThread(content::BrowserThread::ID) OVERRIDE {}
+  virtual void FinalCleanup() OVERRIDE {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserPartsTouch);