Enable touch-initiated drag-drop work on Windows

content/browser/web_contents/web_drag_source_win.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/web_contents/web_drag_source_win.h"
 
 #include "base/bind.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
+#include "content/browser/renderer_host/render_widget_host_view_win.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/browser/web_contents/web_drag_utils_win.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 
 using WebKit::WebDragOperationNone;
 
 namespace content {
@@ skipping 40 matching lines @@
 
   if (!web_contents_)
     return;
 
   gfx::Point client;
   gfx::Point screen;
   GetCursorPositions(source_wnd_, &client, &screen);
   web_contents_->DragSourceEndedAt(client.x(), client.y(),
                                    screen.x(), screen.y(),
                                    WebDragOperationNone);
+  OnDragSourceEnded();
 }
 
 void WebDragSource::OnDragSourceDrop() {
   DCHECK(data_);
   data_->SetInDragLoop(false);
   // On Windows, we check for drag end in IDropSource::QueryContinueDrag which
   // happens before IDropTarget::Drop is called. HTML5 requires the "dragend"
   // event to happen after the "drop" event. Since  Windows calls these two
   // directly after each other we can just post a task to handle the
   // OnDragSourceDrop after the current task.
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(&WebDragSource::DelayedOnDragSourceDrop, this));
 }
 
 void WebDragSource::DelayedOnDragSourceDrop() {
   if (!web_contents_)
     return;
-
   gfx::Point client;
   gfx::Point screen;
   GetCursorPositions(source_wnd_, &client, &screen);
   web_contents_->DragSourceEndedAt(client.x(), client.y(), screen.x(),
                                    screen.y(), WinDragOpToWebDragOp(effect_));
+  OnDragSourceEnded();
+}
+
+void WebDragSource::OnDragSourceEnded() {
+  RenderViewHost* render_view_host = web_contents_->GetRenderViewHost();

[dcheng, 2013/05/24 01:10:37]

Why not just GetRenderWidgetHostView() directly?

[Hongbo Min, 2013/05/27 14:51:41]

Done.

+  if (!render_view_host)
+    return;
+
+  RenderWidgetHostViewWin* rwhv =
+      static_cast<RenderWidgetHostViewWin*>(render_view_host->GetView());
+  if (rwhv->in_long_press_gesture())
+    rwhv->CancelLongPressGesture();
 }
 
 void WebDragSource::OnDragSourceMove() {
   // Delegate to the UI thread if we do drag-and-drop in the background thread.
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         base::Bind(&WebDragSource::OnDragSourceMove, this));
     return;
   }
 
   if (!web_contents_)
     return;
 
   gfx::Point client;
   gfx::Point screen;
   GetCursorPositions(source_wnd_, &client, &screen);
   web_contents_->DragSourceMovedTo(client.x(), client.y(),
                                    screen.x(), screen.y());
 }
 
+bool WebDragSource::ShouldDropDragSource(
+    BOOL escape_pressed, DWORD key_state) {
+  // We also care about right mouse button state since long press gesture is
+  // simulated as right mouse button down/up.
+  LOG(INFO) << "call WebDragSource::ShouldDropDragSource: key_state: "
+            << key_state;
+
+  return !(key_state & MK_LBUTTON) && !(key_state & MK_RBUTTON);

[dcheng, 2013/05/24 01:10:37]

I would prefer to see the right-mouse button check more tightly bound to the
fact that it's due to a touch-initiated drag. In fact, I think we should just
move this logic into DragSourceWin in ui/base/dragdrop. Basically, DragSourceWin
would take an enum in its constructor that indicates whether it's for a touch or
mouse-initiated drag. Then QueryContinueDrag could simply use that to check.

[Hongbo Min, 2013/05/27 14:51:41]

Good suggestion, thanks. Done! 

+}
+
 void WebDragSource::Observe(int type,
                             const NotificationSource& source,
                             const NotificationDetails& details) {
   if (type == NOTIFICATION_WEB_CONTENTS_SWAPPED) {
     // When the WebContents get swapped, our render view host goes away.
     // That's OK, we can continue the drag, we just can't send messages back to
     // our drag source.
     web_contents_ = NULL;
   } else if (type == NOTIFICATION_WEB_CONTENTS_DISCONNECTED) {
     // This could be possible when we close the tab and the source is still
     // being used in DoDragDrop at the time that the virtual file is being
     // downloaded.
     web_contents_ = NULL;
   }
 }
 
 }  // namespace content