Prevent Plugin Channel Host from dropping reply messages while plugins are disabled; do not create plugins while plugin messages are being dropped.

Review URL: http://codereview.chromium.org/69021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@13905 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 28 insertions, 13 deletions

diff --git a/chrome/renderer/plugin_channel_host.cc b/chrome/renderer/plugin_channel_host.cc
index 3759de1..b206f0e 100644
--- a/chrome/renderer/plugin_channel_host.cc
+++ b/chrome/renderer/plugin_channel_host.cc
@@ -26,26 +26,36 @@ class IsListeningFilter : public IPC::ChannelProxy::MessageFilter {
 };
 
 bool IsListeningFilter::OnMessageReceived(const IPC::Message& message) {
-  bool handled = true;
-  if (!IsListeningFilter::is_listening_) {
-    // reply to synchronous messages with an error (so they don't block while
-    // we're not listening)
-    if (message.is_sync()) {
-      IPC::Message* reply = IPC::SyncMessage::GenerateReply(&message);
-      reply->set_reply_error();
-      channel_->Send(reply);
-    }
-    handled = true;
-  } else {
-    handled = false;
+  if (IsListeningFilter::is_listening_) {
+    // Proceed with normal operation.
+    return false;
   }
-  return handled;
+
+  // Always process message reply to prevent renderer from hanging on sync
+  // messages.
+  if (message.is_reply() || message.is_reply_error()) {
+    return false;
+  }
+
+  // Reply to synchronous messages with an error (so they don't block while
+  // we're not listening).
+  if (message.is_sync()) {
+    IPC::Message* reply = IPC::SyncMessage::GenerateReply(&message);
+    reply->set_reply_error();
+    channel_->Send(reply);
+  }
+  return true;
 }
 
 // static
 bool IsListeningFilter::is_listening_ = true;
 
 // static
+bool PluginChannelHost::IsListening() {
+  return IsListeningFilter::is_listening_;
+}
+
+// static
 void PluginChannelHost::SetListening(bool flag) {
   IsListeningFilter::is_listening_ = flag;
 }
diff --git a/chrome/renderer/plugin_channel_host.h b/chrome/renderer/plugin_channel_host.h
index 6edbadd..446ef5c 100644
--- a/chrome/renderer/plugin_channel_host.h
+++ b/chrome/renderer/plugin_channel_host.h
@@ -31,6 +31,8 @@ class PluginChannelHost : public PluginChannelBase {
 
   static void SetListening(bool flag);
 
+  static bool IsListening();
+
  private:
   // Called on the render thread
   PluginChannelHost();
diff --git a/chrome/renderer/render_view.cc b/chrome/renderer/render_view.cc
index f5ca189..c0b13f2 100644
--- a/chrome/renderer/render_view.cc
+++ b/chrome/renderer/render_view.cc
@@ -1875,6 +1875,9 @@ WebPluginDelegate* RenderView::CreatePluginDelegate(
     const std::string& clsid,
     std::string* actual_mime_type) {
 #if defined(OS_WIN)
+  if (!PluginChannelHost::IsListening())
+    return NULL;
+
   if (RenderProcess::current()->in_process_plugins()) {
     FilePath path;
     render_thread_->Send(