Add chrome_split_dll gyp variable, and duplicate chrome_main_dll target (reland)

content/browser/renderer_host/render_process_host_impl.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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 478 matching lines @@
 #endif
       new IPC::ChannelProxy(
           channel_id, IPC::Channel::MODE_SERVER, this,
           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)));
 
   // Call the embedder first so that their IPC filters have priority.
   GetContentClient()->browser()->RenderProcessHostCreated(this);
 
   CreateMessageFilters();
 
+  // Single-process mode not supported in split-dll mode.
+#if !defined(CHROME_SPLIT_DLL)
   if (run_renderer_in_process()) {
     // Crank up a thread and run the initialization there.  With the way that
     // messages flow between the browser and renderer, this thread is required
     // to prevent a deadlock in single-process mode.  Since the primordial
     // thread in the renderer process runs the WebKit code and can sometimes
     // make blocking calls to the UI thread (i.e. this thread), they need to run
     // on separate threads.
     in_process_renderer_.reset(new RendererMainThread(channel_id));
 
     base::Thread::Options options;
 #if defined(OS_WIN) && !defined(OS_MACOSX)
     // In-process plugins require this to be a UI message loop.
     options.message_loop_type = base::MessageLoop::TYPE_UI;
 #else
     // We can't have multiple UI loops on Linux and Android, so we don't support
     // in-process plugins.
     options.message_loop_type = base::MessageLoop::TYPE_DEFAULT;
 #endif
     in_process_renderer_->StartWithOptions(options);
 
     OnProcessLaunched();  // Fake a callback that the process is ready.
-  } else {
+  } else
+#endif  // !CHROME_SPLIT_DLL
+  {
     // Build command line for renderer.  We call AppendRendererCommandLine()
     // first so the process type argument will appear first.
     CommandLine* cmd_line = new CommandLine(renderer_path);
     if (!renderer_prefix.empty())
       cmd_line->PrependWrapper(renderer_prefix);
     AppendRendererCommandLine(cmd_line);
     cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
 
     // Spawn the child process asynchronously to avoid blocking the UI thread.
     // As long as there's no renderer prefix, we can use the zygote process
@@ skipping 1211 matching lines @@
   TRACE_EVENT0("renderer_host",
                "RenderWidgetHostImpl::OnCompositorSurfaceBuffersSwappedNoHost");
   AcceleratedSurfaceMsg_BufferPresented_Params ack_params;
   ack_params.sync_point = 0;
   RenderWidgetHostImpl::AcknowledgeBufferPresent(route_id,
                                                  gpu_process_host_id,
                                                  ack_params);
 }
 
 }  // namespace content