Add an identity (id) to system drag & drop.

Used for gears file drag & drop in chrome, assign a drag id (identity) to
each drag and drop session.

Send the identity to the renderer WebViewImpl in drag enter notifications,
provide a getter method.

BUG=7995

Original patch by noel.gordon@gmail.com in:
http://codereview.chromium.org/28108/show

Review URL: http://codereview.chromium.org/28158

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@10430 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 45 insertions, 1 deletions

diff --git a/webkit/glue/webdropdata.h b/webkit/glue/webdropdata.h
index 9afcd04..7c9fe19 100644
--- a/webkit/glue/webdropdata.h
+++ b/webkit/glue/webdropdata.h
@@ -16,7 +16,15 @@
 struct IDataObject;
 
 struct WebDropData {
-  // User is dropping a link on the webview.
+  // Construct with a given drag identity.  Note: identity is an int32 because
+  // it is passed over the renderer NPAPI interface to gears.
+  explicit WebDropData(int32 drag_identity) : identity(drag_identity) {}
+  int32 identity;
+
+  // For default constructions, use drag |identity| 0.
+  WebDropData() : identity(0) {}
+
+  // User is dragging a link into the webview.
   GURL url;
   std::wstring url_title;  // The title associated with |url|.
 
diff --git a/webkit/glue/webview.h b/webkit/glue/webview.h
index fbd4f33f..d8ef94d 100644
--- a/webkit/glue/webview.h
+++ b/webkit/glue/webview.h
@@ -185,6 +185,7 @@ class WebView : public WebWidget {
   virtual void DragTargetDragLeave() = 0;
   virtual void DragTargetDrop(
       int client_x, int client_y, int screen_x, int screen_y) = 0;
+  virtual int32 GetDragIdentity() = 0;
 
   // Notifies the webview that autofill suggestions are available for a node.
   virtual void AutofillSuggestionsForNode(
diff --git a/webkit/glue/webview_impl.cc b/webkit/glue/webview_impl.cc
index 6b0444d..4db2ac0 100644
--- a/webkit/glue/webview_impl.cc
+++ b/webkit/glue/webview_impl.cc
@@ -334,6 +334,8 @@ WebViewImpl::WebViewImpl()
       suppress_next_keypress_event_(false),
       window_open_disposition_(IGNORE_ACTION),
       ime_accept_events_(true),
+      drag_target_dispatch_(false),
+      drag_identity_(0),
       autocomplete_popup_showing_(false) {
   // WebKit/win/WebView.cpp does the same thing, except they call the
   // KJS specific wrapper around this method. We need to have threading
@@ -1472,37 +1474,61 @@ bool WebViewImpl::DragTargetDragEnter(const WebDropData& drop_data,
   DCHECK(!current_drop_data_.get());
 
   current_drop_data_ = webkit_glue::WebDropDataToChromiumDataObject(drop_data);
+  drag_identity_ = drop_data.identity;
 
   DragData drag_data(current_drop_data_.get(), IntPoint(client_x, client_y),
       IntPoint(screen_x, screen_y), kDropTargetOperation);
+  drag_target_dispatch_ = true;
   DragOperation effect = page_->dragController()->dragEntered(&drag_data);
+  drag_target_dispatch_ = false;
+
   return effect != DragOperationNone;
 }
 
 bool WebViewImpl::DragTargetDragOver(
     int client_x, int client_y, int screen_x, int screen_y) {
   DCHECK(current_drop_data_.get());
+
   DragData drag_data(current_drop_data_.get(), IntPoint(client_x, client_y),
       IntPoint(screen_x, screen_y), kDropTargetOperation);
+  drag_target_dispatch_ = true;
   DragOperation effect = page_->dragController()->dragUpdated(&drag_data);
+  drag_target_dispatch_ = false;
+
   return effect != DragOperationNone;
 }
 
 void WebViewImpl::DragTargetDragLeave() {
   DCHECK(current_drop_data_.get());
+
   DragData drag_data(current_drop_data_.get(), IntPoint(), IntPoint(),
                      DragOperationNone);
+  drag_target_dispatch_ = true;
   page_->dragController()->dragExited(&drag_data);
+  drag_target_dispatch_ = false;
+
   current_drop_data_ = NULL;
+  drag_identity_ = 0;
 }
 
 void WebViewImpl::DragTargetDrop(
     int client_x, int client_y, int screen_x, int screen_y) {
   DCHECK(current_drop_data_.get());
+
   DragData drag_data(current_drop_data_.get(), IntPoint(client_x, client_y),
       IntPoint(screen_x, screen_y), kDropTargetOperation);
+  drag_target_dispatch_ = true;
   page_->dragController()->performDrag(&drag_data);
+  drag_target_dispatch_ = false;
+
   current_drop_data_ = NULL;
+  drag_identity_ = 0;
+}
+
+int32 WebViewImpl::GetDragIdentity() {
+  if (drag_target_dispatch_)
+    return drag_identity_;
+  return 0;
 }
 
 SearchableFormData* WebViewImpl::CreateSearchableFormDataForFocusedNode() {
diff --git a/webkit/glue/webview_impl.h b/webkit/glue/webview_impl.h
index 9023d96..2c0a118 100644
--- a/webkit/glue/webview_impl.h
+++ b/webkit/glue/webview_impl.h
@@ -100,6 +100,7 @@ class WebViewImpl : public WebView, public base::RefCounted<WebViewImpl> {
   virtual void DragTargetDragLeave();
   virtual void DragTargetDrop(
       int client_x, int client_y, int screen_x, int screen_y);
+  virtual int32 GetDragIdentity();
   virtual void AutofillSuggestionsForNode(
       int64 node_id,
       const std::vector<std::wstring>& suggestions,
@@ -294,6 +295,14 @@ class WebViewImpl : public WebView, public base::RefCounted<WebViewImpl> {
   // Represents whether or not this object should process incoming IME events.
   bool ime_accept_events_;
 
+  // True while dispatching system drag and drop events to drag/drop targets
+  // within this WebView.
+  bool drag_target_dispatch_;
+
+  // Valid when drag_target_dispatch_ is true; the identity of the drag data
+  // copied from the WebDropData object sent from the browser process.
+  int32 drag_identity_;
+
   // The autocomplete popup.  Kept around and reused every-time new suggestions
   // should be shown.
   RefPtr<WebCore::PopupContainer> autocomplete_popup_;