Reland r59972: Eagerly set the IO loop used for OCSP.

net/url_request/url_request_context.h

Index: net/url_request/url_request_context.h
diff --git a/net/url_request/url_request_context.h b/net/url_request/url_request_context.h
index 6ddc940c2d623151bb142b0194fa02a5c51e4080..548d0c68c898585075f3584813523bcf3ac00747 100644
--- a/net/url_request/url_request_context.h
+++ b/net/url_request/url_request_context.h
@@ -104,6 +104,11 @@ class URLRequestContext
     referrer_charset_ = charset;
   }
 
+  // Controls whether or not the URLRequestContext considers itself to be the
+  // "main" URLRequestContext.
+  bool is_main() const { return is_main_; }
+  void set_is_main(bool is_main) { is_main_ = is_main; }
+
  protected:
   friend class base::RefCountedThreadSafe<URLRequestContext>;
 
@@ -131,6 +136,9 @@ class URLRequestContext
   std::string referrer_charset_;
 
  private:
+  // Indicates whether or not this is the main URLRequestContext.
+  bool is_main_;
+
   DISALLOW_COPY_AND_ASSIGN(URLRequestContext);
 };