Enable spare RenderProcessHost to be preinitialized.

content/browser/browser_context.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/public/browser/browser_context.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 350 matching lines @@
                           base::Bind(ShutdownServiceWorkerContext));
 
   // Shared workers also keep render process hosts alive, and are expected to
   // return ref counts to 0 after documents close. However, shared worker
   // bookkeeping is done on the IO thread and we want to ensure the hosts are
   // destructed now, so forcibly release their ref counts here.
   for (RenderProcessHost::iterator host_iterator =
            RenderProcessHost::AllHostsIterator();
        !host_iterator.IsAtEnd(); host_iterator.Advance()) {
     RenderProcessHost* host = host_iterator.GetCurrentValue();
-    if (host->GetBrowserContext() == browser_context)
+    if (host->GetBrowserContext() == browser_context) {
+      // This will also clean up spare RPH references.
       host->ForceReleaseWorkerRefCounts();
+    }
   }
 }
 
 void BrowserContext::EnsureResourceContextInitialized(BrowserContext* context) {
   // This will be enough to tickle initialization of BrowserContext if
   // necessary, which initializes ResourceContext. The reason we don't call
   // ResourceContext::InitializeResourceContext() directly here is that
   // ResourceContext initialization may call back into BrowserContext
   // and when that call returns it'll end rewriting its UserData map. It will
   // end up rewriting the same value but this still causes a race condition.
@@ skipping 179 matching lines @@
 
 // static
 std::string BrowserContext::CreateRandomMediaDeviceIDSalt() {
   std::string salt;
   base::Base64Encode(base::RandBytesAsString(16), &salt);
   DCHECK(!salt.empty());
   return salt;
 }
 
 }  // namespace content