Drag-and-drop: Target drag messages (the sequel).

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 86257b48c45cb766d5dd5f20f7056b88c1bc4b9d..650b4cc575a09fbd86081f1056138c7b430742cd 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -80,6 +80,7 @@
 #include "content/browser/webui/web_ui_impl.h"
 #include "content/common/browser_plugin/browser_plugin_constants.h"
 #include "content/common/browser_plugin/browser_plugin_messages.h"
+#include "content/common/drag_messages.h"
 #include "content/common/frame_messages.h"
 #include "content/common/input_messages.h"
 #include "content/common/page_messages.h"
@@ -3018,10 +3019,16 @@ void WebContentsImpl::NotifyWebContentsFocused() {
 }
 
 void WebContentsImpl::SystemDragEnded() {
-  // TODO(paulmeyer): This will need to target the correct specific RWH to work
-  // with OOPIF.
-  if (GetRenderViewHost())
-    GetRenderViewHost()->GetWidget()->DragSourceSystemDragEnded();
+  // TODO(lukasza/paulmeyer): Rather then sending the IPC to all widgets in the
+  // frame tree, it might be possible to send the IPC only to the widget where
+  // drag-start has fired.
+  for (RenderWidgetHostView* rwhv : GetRenderWidgetHostViewsInTree()) {
+    RenderWidgetHostViewBase* rwhvb =
+        static_cast<RenderWidgetHostViewBase*>(rwhv);
+    RenderWidgetHost* rwh = rwhvb->GetRenderWidgetHost();
+    rwh->Send(new DragMsg_SourceSystemDragEnded(rwh->GetRoutingID()));

[dcheng, 2016/11/17 17:44:19]

We should definitely only be sending this to the drag source. The renderer
happens to guard against dragends that should be no-ops, but we shouldn't be
relying on that.

(Looking at this more, it seems like our DnD code is generally confused about
what it should be doing here: I think we're actually sending both
DragMsg_SourceEnded (which dispatches the dragend event) and
DragMsg_SourceSystemDragEnded in the normal DnD completion scenario... but it's
OK to fix that later)

+  }
+
   if (browser_plugin_embedder_.get())
     browser_plugin_embedder_->SystemDragEnded();
 }