Fixed drag and drop into and out of Browser Plugin.

content/browser/browser_plugin/browser_plugin_embedder.cc

Index: content/browser/browser_plugin/browser_plugin_embedder.cc
diff --git a/content/browser/browser_plugin/browser_plugin_embedder.cc b/content/browser/browser_plugin/browser_plugin_embedder.cc
index 4ffaa3d7b383bdb45bb84d562e2a17ae8b070f4e..6171f0c333cfe57f88f4481ff59f4d70c7fd0a51 100644
--- a/content/browser/browser_plugin/browser_plugin_embedder.cc
+++ b/content/browser/browser_plugin/browser_plugin_embedder.cc
@@ -11,6 +11,7 @@
 #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/drag_messages.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
@@ -195,6 +196,22 @@ BrowserPluginGuest* BrowserPluginEmbedder::GetGuestByInstanceID(
   return NULL;
 }
 
+void BrowserPluginEmbedder::DragEnteredGuest(BrowserPluginGuest* guest) {

[Fady Samuel, 2013/02/01 16:59:53]

SetDragEnteredGuest I'm a bit concerned about lifetime issues (what if we
attempt to remove a BrowserPlugin as we're dragging). Maybe we should
have a weak pointer to BrowserPluginGuest?

[mthiesse, 2013/02/07 15:28:55]

Done.

+  guest_dragging_over = guest;
+}
+
+void BrowserPluginEmbedder::DragLeftGuest(BrowserPluginGuest* guest) {

[Fady Samuel, 2013/02/01 16:59:53]

SetDragLeftGuest. I'm a bit concerned about lifetime issues. Maybe we should
have a weak pointer to BrowserPluginGuest?

[mthiesse, 2013/02/07 15:28:55]

Done.

+  // Avoid race conditions in switching between guests being hovered over by
+  // only un-setting if the caller is marked as the guest being dragged over.
+  if (guest_dragging_over == guest) {
+    guest_dragging_over = NULL;
+  }
+}
+
+void BrowserPluginEmbedder::StartDrag(BrowserPluginGuest* guest) {
+  guest_started_drag = guest;
+}
+
 void BrowserPluginEmbedder::DestroyGuestByInstanceID(int instance_id) {
   BrowserPluginGuest* guest = GetGuestByInstanceID(instance_id);
   if (guest) {
@@ -228,6 +245,17 @@ void BrowserPluginEmbedder::RenderViewGone(base::TerminationStatus status) {
 }
 
 bool BrowserPluginEmbedder::OnMessageReceived(const IPC::Message& message) {
+  if (message.type() == DragHostMsg_DragStopped::ID) {
+    if (guest_started_drag)

[Fady Samuel, 2013/02/01 16:59:53]

Please move this and UpdateDragCursor to separate message handlers so as to
avoid cluttering OnMessageReceived.

[mthiesse, 2013/02/07 15:28:55]

Done.

+      return guest_started_drag->OnMessageReceived(message);
+  }
+  if (message.type() == DragHostMsg_UpdateDragCursor::ID){
+    // If the guest is being dragged over we want to mark this as handled so
+    // that we don't update the cursor twice, once by the guest, and once by the
+    // embedder (and have the cursor flicker between droppable and
+    // non-droppable).
+    return (guest_dragging_over);
+  }
   if (ShouldForwardToBrowserPluginGuest(message)) {
     int instance_id = 0;
     // All allowed messages must have instance_id as their first parameter.