Created a new BrowserMessageFilter to handle print related IPC messages.

chrome/browser/renderer_host/browser_render_process_host.cc

Index: chrome/browser/renderer_host/browser_render_process_host.cc
diff --git a/chrome/browser/renderer_host/browser_render_process_host.cc b/chrome/browser/renderer_host/browser_render_process_host.cc
index be7cc299c1324d0698f801ed903e6dcb9272327c..d20de3059be8d44dd8513f6d685b367acaf5146e 100644
--- a/chrome/browser/renderer_host/browser_render_process_host.cc
+++ b/chrome/browser/renderer_host/browser_render_process_host.cc
@@ -88,6 +88,7 @@
 #include "chrome/common/result_codes.h"
 #include "chrome/renderer/render_process_impl.h"
 #include "chrome/renderer/render_thread.h"
+#include "content/browser/renderer_host/printing_message_filter.h"

[kmadhusu, 2011/02/21 21:30:04]

jam: Do I need a dummy file
"chrome/browser/renderer_host/printing_message_filter.h" to include
"content/browser/renderer_host/printing_message_filter.h" or is this ok?

[Lei Zhang, 2011/02/22 19:37:42]

This should be fine. Nobody is referring to the file at the old location since
this is a new file.

[jam, 2011/02/22 20:29:41]

actually, the printing code will remain in src\chrome, and not src\content.  The
latter is the minimum required to render a page in a multi-process browser. 
Features like printing, autofill etc are what's provided by the embedder.

[kmadhusu, 2011/02/23 02:27:49]

Done. Moved printing_message_filter from src/content to
src/chrome/browser/printing.

 #include "grit/generated_resources.h"
 #include "ipc/ipc_logging.h"
 #include "ipc/ipc_message.h"
@@ -457,6 +458,7 @@ void BrowserRenderProcessHost::CreateMessageFilters() {
   channel_->AddFilter(new GpuMessageFilter(id()));
   channel_->AddFilter(new PepperFileMessageFilter(id(), profile()));
   channel_->AddFilter(new PepperMessageFilter(profile()));
+  channel_->AddFilter(new PrintingMessageFilter());
   channel_->AddFilter(new speech_input::SpeechInputDispatcherHost(id()));
   channel_->AddFilter(
       new SearchProviderInstallStateMessageFilter(id(), profile()));