Adds a --deterministic-fetch flag to headless_shell

headless/public/headless_browser_context.h

Index: headless/public/headless_browser_context.h
diff --git a/headless/public/headless_browser_context.h b/headless/public/headless_browser_context.h
index 4cdaf3559c2cd608e4db5356b4fe799e1652ea14..55847ef0d497a95afdf92f4e77591928199e8c3c 100644
--- a/headless/public/headless_browser_context.h
+++ b/headless/public/headless_browser_context.h
@@ -17,6 +17,14 @@
 #include "net/base/host_port_pair.h"
 #include "net/url_request/url_request_job_factory.h"
 
+namespace base {
+class FilePath;
+}  // namespace base
+
+namespace net {
+class URLRequestContext;
+}  // namespace net
+
 namespace headless {
 class HeadlessBrowserImpl;
 class HeadlessBrowserContextOptions;
@@ -55,6 +63,9 @@ class HEADLESS_EXPORT HeadlessBrowserContext {
   // GUID for this browser context.
   virtual const std::string& Id() const = 0;
 
+  // Returns the URLRequestContext associated with this browser context.
+  virtual net::URLRequestContext* GetRequestContext() const = 0;
+
   // TODO(skyostil): Allow saving and restoring contexts (crbug.com/617931).
 
  protected: