Remove long gone Windows side of the BackgroundRendererProcesses experiment.

content/browser/renderer_host/render_process_host_impl.cc

Index: content/browser/renderer_host/render_process_host_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 2c00dff52930b46a7a7747b3508974658d066e34..2d7b7e6b484d5131d7c1f180df7e279a05bf5c50 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -29,7 +29,6 @@
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
-#include "base/strings/string_util.h"
 #include "base/supports_user_data.h"
 #include "base/sys_info.h"
 #include "base/threading/thread.h"
@@ -2314,24 +2313,12 @@ void RenderProcessHostImpl::SetBackgrounded(bool backgrounded) {
     return;
 #endif  // OS_WIN
 
-#if defined(OS_WIN)
-  // Same as below, but bound to an experiment (http://crbug.com/458594 ).
-  // Enabled by default in the absence of field trials to get coverage on the
-  // perf waterfall.
-  base::FieldTrial* trial =
-      base::FieldTrialList::Find("BackgroundRendererProcesses");
-  if (!trial || !base::StartsWith(trial->group_name(), "Disallow",
-                                  base::CompareCase::SENSITIVE)) {
-    child_process_launcher_->SetProcessBackgrounded(backgrounded);
-  }
-#else
   // Control the background state from the browser process, otherwise the task
   // telling the renderer to "unbackground" itself may be preempted by other
   // tasks executing at lowered priority ahead of it or simply by not being
   // swiftly scheduled by the OS per the low process priority
   // (http://crbug.com/398103).
   child_process_launcher_->SetProcessBackgrounded(backgrounded);
-#endif  // OS_WIN
 
   // Notify the child process of background state.
   Send(new ChildProcessMsg_SetProcessBackgrounded(backgrounded));