Register a default instance of FeatureList for content browser.

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index 32298516aab616ada664c5d6989ff3dcb27c6803..4e7537c9604945af8115ce3c8b1200f9364198c3 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -6,6 +6,7 @@
 
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/memory_pressure_monitor.h"
@@ -690,6 +691,10 @@ int BrowserMainLoop::PreCreateThreads() {
     result_code_ = parts_->PreCreateThreads();
   }
 
+  // Initialize an instance of FeatureList. This will be a no-op if an instance
+  // was already set up by the embedder.
+  base::FeatureList::InitializeInstance();
+
   // TODO(chrisha): Abstract away this construction mess to a helper function,
   // once MemoryPressureMonitor is made a concrete class.
 #if defined(OS_CHROMEOS)