dragend fix for mac <webview>.

content/browser/browser_plugin/browser_plugin_embedder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/browser_plugin/browser_plugin_embedder.h"
 
 #include "base/values.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"
@@ skipping 10 matching lines @@
 #include "content/public/common/content_switches.h"
 #include "content/public/common/result_codes.h"
 #include "content/public/common/url_constants.h"
 #include "net/base/escape.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 
 namespace content {
 
 BrowserPluginEmbedder::BrowserPluginEmbedder(WebContentsImpl* web_contents)
     : WebContentsObserver(web_contents),
+      seen_system_drag_ended_(false),
+      seen_drag_source_ended_at_(false),

[Fady Samuel, 2014/08/21 23:36:31]

Can we do this with one flag?

[lazyboy, 2014/08/22 00:03:27]

Done.

       weak_ptr_factory_(this) {
 }
 
 BrowserPluginEmbedder::~BrowserPluginEmbedder() {
 }
 
 // static
 BrowserPluginEmbedder* BrowserPluginEmbedder::Create(
     WebContentsImpl* web_contents) {
   return new BrowserPluginEmbedder(web_contents);
 }
 
 void BrowserPluginEmbedder::DragEnteredGuest(BrowserPluginGuest* guest) {
   guest_dragging_over_ = guest->AsWeakPtr();
 }
 
 void BrowserPluginEmbedder::DragLeftGuest(BrowserPluginGuest* guest) {
   // 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_.get() == guest) {
     guest_dragging_over_.reset();
   }
 }
 
 void BrowserPluginEmbedder::StartDrag(BrowserPluginGuest* guest) {
   guest_started_drag_ = guest->AsWeakPtr();
+  seen_system_drag_ended_ = false;
+  seen_drag_source_ended_at_ = false;
 }
 
 WebContentsImpl* BrowserPluginEmbedder::GetWebContents() const {
   return static_cast<WebContentsImpl*>(web_contents());
 }
 
 BrowserPluginGuestManager*
 BrowserPluginEmbedder::GetBrowserPluginGuestManager() const {
   return GetWebContents()->GetBrowserContext()->GetGuestManager();
 }
 
+void BrowserPluginEmbedder::ClearGuestDragStateIfApplicable() {
+  // The order at which we observe SystemDragEnded() and DragSourceEndedAt() is
+  // platform dependent.
+  // In OSX, we see SystemDragEnded() first, where in aura, we see
+  // DragSourceEndedAt() first. For this reason, we check if both methods were
+  // called before resetting |guest_started_drag_|.
+  if (guest_started_drag_ && seen_drag_source_ended_at_ &&
+      seen_system_drag_ended_) {
+    guest_started_drag_.reset();
+  }
+}
+
 bool BrowserPluginEmbedder::DidSendScreenRectsCallback(
    WebContents* guest_web_contents) {
   static_cast<RenderViewHostImpl*>(
       guest_web_contents->GetRenderViewHost())->SendScreenRects();
   // Not handled => Iterate over all guests.
   return false;
 }
 
 void BrowserPluginEmbedder::DidSendScreenRects() {
   GetBrowserPluginGuestManager()->ForEachGuest(
           GetWebContents(), base::Bind(
               &BrowserPluginEmbedder::DidSendScreenRectsCallback,
               base::Unretained(this)));
 }
 
 bool BrowserPluginEmbedder::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(BrowserPluginEmbedder, message)
     IPC_MESSAGE_HANDLER(BrowserPluginHostMsg_Attach, OnAttach)
     IPC_MESSAGE_HANDLER_GENERIC(DragHostMsg_UpdateDragCursor,
                                 OnUpdateDragCursor(&handled));
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void BrowserPluginEmbedder::DragSourceEndedAt(int client_x, int client_y,
     int screen_x, int screen_y, blink::WebDragOperation operation) {
-  if (guest_started_drag_.get()) {
+  seen_drag_source_ended_at_ = true;
+  if (guest_started_drag_) {
     gfx::Point guest_offset =
         guest_started_drag_->GetScreenCoordinates(gfx::Point());
     guest_started_drag_->DragSourceEndedAt(client_x - guest_offset.x(),
         client_y - guest_offset.y(), screen_x, screen_y, operation);
   }
+  ClearGuestDragStateIfApplicable();
 }
 
 void BrowserPluginEmbedder::SystemDragEnded() {
   // When the embedder's drag/drop operation ends, we need to pass the message
   // to the guest that initiated the drag/drop operation. This will ensure that
   // the guest's RVH state is reset properly.
-  if (guest_started_drag_.get())
+  seen_system_drag_ended_ = true;
+  if (guest_started_drag_)
     guest_started_drag_->EndSystemDrag();
-  guest_started_drag_.reset();
   guest_dragging_over_.reset();
+  ClearGuestDragStateIfApplicable();
 }
 
 void BrowserPluginEmbedder::OnUpdateDragCursor(bool* handled) {
   *handled = (guest_dragging_over_.get() != NULL);
 }
 
 void BrowserPluginEmbedder::OnGuestCallback(
     int instance_id,
     const BrowserPluginHostMsg_Attach_Params& params,
     const base::DictionaryValue* extra_params,
@@ skipping 38 matching lines @@
   *mouse_unlocked |= static_cast<WebContentsImpl*>(guest)
                          ->GetBrowserPluginGuest()
                          ->mouse_locked();
   guest->GotResponseToLockMouseRequest(false);
 
   // Returns false to iterate over all guests.
   return false;
 }
 
 }  // namespace content