Bug 549888: Have the browser win NPP_SetWindow races, and add a special-cased NPP_HandleEvent async WindowPosChanged message for windows. r=jimm,karlt

dom/plugins/PPluginInstance.ipdl

@@ -79,9 +79,11 @@ child:
 
   rpc NPP_HandleEvent(NPRemoteEvent event)
     returns (int16_t handled);
-  // special case of HandleEvent to make mediating races simpler
+  // special cases of HandleEvent to make mediating races simpler
   rpc Paint(NPRemoteEvent event)
     returns (int16_t handled);
+  // this is only used on windows to forward WM_WINDOWPOSCHANGE
+  async WindowPosChanged(NPRemoteEvent event);
 
   rpc NPP_Destroy()
     returns (NPError rv);

dom/plugins/PluginInstanceChild.cpp

@@ -499,6 +499,19 @@ PluginInstanceChild::AnswerNPP_HandleEvent(const NPRemoteEvent& event,
     return true;
 }
 
+bool
+PluginInstanceChild::RecvWindowPosChanged(const NPRemoteEvent& event)
+{
+#ifdef OS_WIN
+    int16_t dontcare;
+    return AnswerNPP_HandleEvent(event, &dontcare);
+#else
+    NS_RUNTIMEABORT("WindowPosChanged is a windows-only message");
+    return false;
+#endif
+}
+
+
 #if defined(MOZ_X11) && defined(XP_UNIX) && !defined(XP_MACOSX)
 static bool
 XVisualIDToInfo(Display* aDisplay, VisualID aVisualID,

dom/plugins/PluginInstanceChild.h

@@ -96,6 +96,10 @@ protected:
         return AnswerNPP_HandleEvent(event, handled);
     }
 
+    NS_OVERRIDE
+    virtual bool
+    RecvWindowPosChanged(const NPRemoteEvent& event);
+
     virtual bool
     AnswerNPP_Destroy(NPError* result);
 

dom/plugins/PluginInstanceParent.cpp

@@ -566,6 +566,16 @@ PluginInstanceParent::NPP_HandleEvent(void* event)
               }
             }
             break;
+
+            case WM_WINDOWPOSCHANGED:
+            {
+                // We send this in nsObjectFrame just before painting
+                SendWindowPosChanged(npremoteevent);
+                // nsObjectFrame doesn't care whether we handle this
+                // or not, just returning 1 for good hygiene
+                return 1;
+            }
+            break;
         }
     }
 #endif

dom/plugins/PluginMessageUtils.cpp

@@ -82,10 +82,16 @@ RPCChannel::RacyRPCPolicy
 MediateRace(const RPCChannel::Message& parent,
             const RPCChannel::Message& child)
 {
-  // our code relies on the frame list not changing during paints
-  bool isPaint = (PPluginInstance::Msg_Paint__ID == parent.type());
+  switch (parent.type()) {
+  case PPluginInstance::Msg_Paint__ID:
+  case PPluginInstance::Msg_NPP_SetWindow__ID:
+    // our code relies on the frame list not changing during paints and
+    // reflows
+    return RPCChannel::RRPParentWins;
 
-  return isPaint ? RPCChannel::RRPParentWins : RPCChannel::RRPChildWins;
+  default:
+    return RPCChannel::RRPChildWins;
+  }
 }
 
 PRLogModuleInfo* gPluginLog = PR_NewLogModule("IPCPlugins");