Add a gyp flag to allow removing dependency on ppapi.

content/browser/renderer_host/render_message_filter.cc

Index: content/browser/renderer_host/render_message_filter.cc
diff --git a/content/browser/renderer_host/render_message_filter.cc b/content/browser/renderer_host/render_message_filter.cc
index 9d6b5b91d8104730610c7c56a308f7de3b2372d6..f22691b7e04d2ae82e60d91fd19fd03cdabdc1fc 100644
--- a/content/browser/renderer_host/render_message_filter.cc
+++ b/content/browser/renderer_host/render_message_filter.cc
@@ -385,6 +385,7 @@ bool RenderMessageFilter::OnMessageReceived(const IPC::Message& message,
     IPC_MESSAGE_HANDLER(ViewHostMsg_DownloadUrl, OnDownloadUrl)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(ViewHostMsg_OpenChannelToPlugin,
                                     OnOpenChannelToPlugin)
+#if defined(ENABLE_PPAPI)

[brettw, 2012/11/30 23:18:12]

Is this necessary? You still keep the .cc functions and the messages are
compiled in no matter what. I'd be inclined to not ifdef this if it's not
necessary.

[nilesh, 2012/12/01 00:41:35]

These methods are compiled in, but are removed by the linker if these references
are ifdefed out.
These methods contain reference to ppapi which are not compiled in. If we remove
ifdef here, then we will need to add ifdefs in these methods.

     IPC_MESSAGE_HANDLER_DELAY_REPLY(ViewHostMsg_OpenChannelToPepperPlugin,
                                     OnOpenChannelToPepperPlugin)
     IPC_MESSAGE_HANDLER(ViewHostMsg_DidCreateOutOfProcessPepperInstance,
@@ -393,6 +394,7 @@ bool RenderMessageFilter::OnMessageReceived(const IPC::Message& message,
                         OnDidDeleteOutOfProcessPepperInstance)
     IPC_MESSAGE_HANDLER(ViewHostMsg_OpenChannelToPpapiBroker,
                         OnOpenChannelToPpapiBroker)
+#endif
     IPC_MESSAGE_HANDLER_GENERIC(ViewHostMsg_UpdateRect,
         render_widget_helper_->DidReceiveBackingStoreMsg(message))
     IPC_MESSAGE_HANDLER(ViewHostMsg_UpdateIsDelayed, OnUpdateIsDelayed)