Enable features API for content shell and webview

chromecast/browser/cast_browser_main_parts.cc

Index: chromecast/browser/cast_browser_main_parts.cc
diff --git a/chromecast/browser/cast_browser_main_parts.cc b/chromecast/browser/cast_browser_main_parts.cc
index b4202898a59a35bdca35fcae6509eb4dc46d85cc..e5823ca8fd6a2984e2310ecf2c1bd9c225aaadbb 100644
--- a/chromecast/browser/cast_browser_main_parts.cc
+++ b/chromecast/browser/cast_browser_main_parts.cc
@@ -10,6 +10,7 @@
 #include <string>
 
 #include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/files/file_util.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
@@ -295,6 +296,19 @@ void CastBrowserMainParts::ToolkitInitialized() {
 }
 
 int CastBrowserMainParts::PreCreateThreads() {
+  // The only case GetInstance() returns null should be when you are running a
+  // C++ test, in which case currently we do not support command line features.
+  // This allows Test::SetUp() to enable/disable features as necessary. See
+  // crbug.com/596021 for more details.
+  if (!base::FeatureList::GetInstance()) {
+    base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+    scoped_ptr<base::FeatureList> feature_list(new base::FeatureList);
+    feature_list->InitializeFromCommandLine(
+        command_line->GetSwitchValueASCII(switches::kEnableFeatures),
+        command_line->GetSwitchValueASCII(switches::kDisableFeatures));
+    base::FeatureList::SetInstance(std::move(feature_list));
+  }
+
 #if defined(OS_ANDROID)
   // GPU process is started immediately after threads are created, requiring
   // CrashDumpManager to be initialized beforehand.