Allow for pausing background tabs on desktop via about:flags.

chrome/renderer/chrome_content_renderer_client.cc

Index: chrome/renderer/chrome_content_renderer_client.cc
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index efc66d43d7ea815176805fa514da7fb5aee08648..b337d6c15442e0a00e840545386d59b45ee19efd 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -28,6 +28,7 @@
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/crash_keys.h"
 #include "chrome/common/features.h"
+#include "chrome/common/pause_tabs_field_trial.h"
 #include "chrome/common/pepper_permission_util.h"
 #include "chrome/common/prerender_types.h"
 #include "chrome/common/render_messages.h"
@@ -1090,7 +1091,8 @@ bool ChromeContentRendererClient::
 #if defined(OS_ANDROID)
   return true;
 #else
-  return false;
+  // TODO(ojan): Plumb the engagement values for this feature to WebViewImpl.
+  return base::FeatureList::IsEnabled(pausetabs::kFeature);
 #endif
 }