Make gpu black list work again on Linux

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 25dcaecd52382a4b387e64a2a6b2a106b179a438..ea6e5b722a20fd4cc450eb64d4a2e5e371055de1 100644
--- a/content/public/browser/browser_main_parts.h
+++ b/content/public/browser/browser_main_parts.h
@@ -68,7 +68,11 @@ class CONTENT_EXPORT BrowserMainParts {
   // The main message loop has been started at this point (but has not
   // been run), and the toolkit has been initialized. Returns the error code
   // (or 0 if no error).
-  virtual int PreCreateThreads();
+  virtual int PreCreateThreadsBegin();
+
+  // Allow to do some jobs after PreCreateThreads() but just before actually
+  // starting threads.
+  virtual void PreCreateThreadsEnd() {}
 
   // This is called just before the main message loop is run.  The
   // various browser threads have all been created at this point