Generate dumps for relevant renderers when users kill a hung pepper plugin.

ppapi/proxy/host_dispatcher.cc

Index: ppapi/proxy/host_dispatcher.cc
diff --git a/ppapi/proxy/host_dispatcher.cc b/ppapi/proxy/host_dispatcher.cc
index 21dc269aabb8bdacdbe28fad3cf37e5d31b47376..b89032a2e40d28ad6666d952d936023d4fb0b71b 100644
--- a/ppapi/proxy/host_dispatcher.cc
+++ b/ppapi/proxy/host_dispatcher.cc
@@ -4,8 +4,6 @@
 
 #include "ppapi/proxy/host_dispatcher.h"
 
-#include <map>
-
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "ppapi/c/private/ppb_proxy_private.h"
@@ -15,6 +13,7 @@
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/proxy/resource_creation_proxy.h"
 #include "ppapi/shared_impl/ppapi_globals.h"
+#include "ppapi/shared_impl/ppapi_message_tracker.h"
 
 namespace ppapi {
 namespace proxy {
@@ -133,6 +132,8 @@ bool HostDispatcher::IsPlugin() const {
 }
 
 bool HostDispatcher::Send(IPC::Message* msg) {
+  ScopedTrackPpapiMessage track_ppapi_message;
+
   TRACE_EVENT2("ppapi proxy", "HostDispatcher::Send",
                "Class", IPC_MESSAGE_ID_CLASS(msg->type()),
                "Line", IPC_MESSAGE_ID_LINE(msg->type()));
@@ -171,6 +172,8 @@ bool HostDispatcher::Send(IPC::Message* msg) {
 }
 
 bool HostDispatcher::OnMessageReceived(const IPC::Message& msg) {
+  ScopedTrackPpapiMessage track_ppapi_message;
+
   TRACE_EVENT2("ppapi proxy", "HostDispatcher::OnMessageReceived",
                "Class", IPC_MESSAGE_ID_CLASS(msg.type()),
                "Line", IPC_MESSAGE_ID_LINE(msg.type()));