Fix losing of scoped feature channel in tests when it's equal to stable

extensions/common/features/feature_channel.h

Index: extensions/common/features/feature_channel.h
diff --git a/extensions/common/features/feature_channel.h b/extensions/common/features/feature_channel.h
index 5533e5d588ce5f6226992202997c65112ecf9350..8807132c0037c4bb0e993b81b06127abd5ef1b2c 100644
--- a/extensions/common/features/feature_channel.h
+++ b/extensions/common/features/feature_channel.h
@@ -16,22 +16,24 @@ namespace extensions {
 // Gets the current channel as seen by the Feature system.
 version_info::Channel GetCurrentChannel();
 
-// Sets the current channel as seen by the Feature system. In the browser
-// process this should be chrome::GetChannel(), and in the renderer this will
-// need to come from an IPC.
+// Sets the current channel as seen by the Feature system, unless the channel is
+// currently set through |ScopedCurrentChannel|. In the browser process this
+// should be chrome::GetChannel(), and in the renderer this will need to come
+// from an IPC.
 void SetCurrentChannel(version_info::Channel channel);
 
-// Gets the default channel as seen by the Feature system.
-version_info::Channel GetDefaultChannel();
-
 // Scoped channel setter. Use for tests.
+// Note that the lifetimes of multiple instances of this class must be disjoint
+// or nested, but never overlapping.
 class ScopedCurrentChannel {
  public:
   explicit ScopedCurrentChannel(version_info::Channel channel);
   ~ScopedCurrentChannel();
 
  private:
-  version_info::Channel original_channel_;
+  const version_info::Channel channel_;
+  const version_info::Channel original_overridden_channel_;
+  const bool original_channel_is_overridden_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedCurrentChannel);
 };