Browser Plugin: Add HTML5-like postMessage support

content/browser/browser_plugin/browser_plugin_embedder_helper.cc

Index: content/browser/browser_plugin/browser_plugin_embedder_helper.cc
diff --git a/content/browser/browser_plugin/browser_plugin_embedder_helper.cc b/content/browser/browser_plugin/browser_plugin_embedder_helper.cc
index 7039b2bb06fa548466dab0491ea084c5bc8387f4..68331cea377f1f05ccdf165f23828c4b720e4eb6 100644
--- a/content/browser/browser_plugin/browser_plugin_embedder_helper.cc
+++ b/content/browser/browser_plugin/browser_plugin_embedder_helper.cc
@@ -5,7 +5,9 @@
 #include "content/browser/browser_plugin/browser_plugin_embedder_helper.h"
 
 #include "content/browser/browser_plugin/browser_plugin_embedder.h"
+#include "content/browser/browser_plugin/browser_plugin_guest.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
+#include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/browser_plugin_messages.h"
 #include "content/common/view_messages.h"
 #include "content/public/browser/render_process_host.h"
@@ -32,6 +34,15 @@ bool BrowserPluginEmbedderHelper::Send(IPC::Message* message) {
 bool BrowserPluginEmbedderHelper::OnMessageReceived(
     const IPC::Message& message) {
   bool handled = true;
+  if (static_cast<content::RenderViewHostImpl*>(render_view_host())->
+          is_swapped_out()) {
+    IPC_BEGIN_MESSAGE_MAP(BrowserPluginEmbedderHelper, message)
+      IPC_MESSAGE_HANDLER(ViewHostMsg_RouteMessageEvent,
+                          OnRouteMessageEvent)
+      IPC_MESSAGE_UNHANDLED(handled = false)
+    IPC_END_MESSAGE_MAP()
+    return handled;
+  }
   IPC_BEGIN_MESSAGE_MAP(BrowserPluginEmbedderHelper, message)
     IPC_MESSAGE_HANDLER(BrowserPluginHostMsg_NavigateGuest,
                         OnNavigateGuest);
@@ -48,6 +59,7 @@ bool BrowserPluginEmbedderHelper::OnMessageReceived(
     IPC_MESSAGE_HANDLER(BrowserPluginHostMsg_Reload, OnReload)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
+
   return handled;
 }
 
@@ -121,6 +133,28 @@ void BrowserPluginEmbedderHelper::OnPluginDestroyed(int instance_id) {
   embedder_->PluginDestroyed(instance_id);
 }
 
+void BrowserPluginEmbedderHelper::OnRouteMessageEvent(
+    const ViewMsg_PostMessage_Params& params) {
+  // This helper's RVH corresponds to a swapped out RenderView living in
+  // the embedder's render process. If this RVH's WebContents has a
+  // BrowserPluginGuest, then we know this is actually a RVH for the
+  // guest for the purpose of catching ViewHostMsg_RouteMessageEvent and
+  // routing it to the guest WebContents.
+  // This code path is executed when the embedder tries to send a message
+  // back through event.source.postMessage within a 'message' event
+  // listener.
+  WebContentsImpl* guest_web_contents = static_cast<WebContentsImpl*>(
+      render_view_host()->GetDelegate());
+  if (!guest_web_contents->GetBrowserPluginGuest())
+    return;
+  embedder_->RouteMessageEvent(
+      guest_web_contents->GetBrowserPluginGuest()->instance_id(),
+      params.data,
+      params.source_frame_id,
+      params.target_origin,
+      params.target_frame_id);
+}
+
 void BrowserPluginEmbedderHelper::OnGo(int instance_id, int relative_index) {
   embedder_->Go(instance_id, relative_index);
 }