Initialize blink only when needed in utility processes.

content/public/utility/utility_thread.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_UTILITY_UTILITY_THREAD_H_
 #define CONTENT_PUBLIC_UTILITY_UTILITY_THREAD_H_
 
 #include "base/basictypes.h"
 #include "content/public/child/child_thread.h"
 
 namespace content {
 
 class CONTENT_EXPORT UtilityThread : virtual public ChildThread {
  public:
   // Returns the one utility thread for this process.  Note that this can only
   // be accessed when running on the utility thread itself.
   static UtilityThread* Get();
 
   UtilityThread();
   ~UtilityThread() override;
 
   // Releases the process if we are not (or no longer) in batch mode.
   virtual void ReleaseProcessIfNeeded() = 0;
+
+  // Initializes blink if it hasn't already been initialized.
+  virtual void EnsureBlinkInitialized() = 0;

[jochen (gone - plz use gerrit), 2015/07/27 11:35:21]

why is this API needed? why not just call initializeWithoutV8() where we used to
call initialize()?

[jam, 2015/07/27 15:14:49]

(see my first message)

to expand on it also, utility process is now for hosting many things that don't
use blink (i.e. mojo apps). so we shouldn't do the work of initializing blink if
we don't need to.

 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_UTILITY_UTILITY_THREAD_H_