Drag-and-drop: Target drag messages to specific RenderWidgets.

content/browser/web_contents/web_contents_view_aura.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_contents_view_aura.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "content/browser/browser_plugin/browser_plugin_guest.h"
 #include "content/browser/download/drag_download_util.h"
 #include "content/browser/frame_host/interstitial_page_impl.h"
 #include "content/browser/frame_host/navigation_entry_impl.h"
 #include "content/browser/renderer_host/dip_util.h"
 #include "content/browser/renderer_host/input/touch_selection_controller_client_aura.h"
 #include "content/browser/renderer_host/overscroll_controller.h"
 #include "content/browser/renderer_host/render_view_host_factory.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
+#include "content/browser/renderer_host/render_widget_host_input_event_router.h"
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 #include "content/browser/web_contents/aura/gesture_nav_simple.h"
 #include "content/browser/web_contents/aura/overscroll_navigation_overlay.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/overscroll_configuration.h"
@@ skipping 470 matching lines @@
 };
 
 ////////////////////////////////////////////////////////////////////////////////
 // WebContentsViewAura, public:
 
 WebContentsViewAura::WebContentsViewAura(WebContentsImpl* web_contents,
                                          WebContentsViewDelegate* delegate)
     : web_contents_(web_contents),
       delegate_(delegate),
       current_drag_op_(blink::WebDragOperationNone),
-      drag_dest_delegate_(NULL),
-      current_rvh_for_drag_(NULL),
+      drag_dest_delegate_(nullptr),
+      current_rvh_for_drag_(nullptr),
       current_overscroll_gesture_(OVERSCROLL_NONE),
       completed_overscroll_gesture_(OVERSCROLL_NONE),
       navigation_overlay_(nullptr),
       init_rwhv_with_null_parent_for_testing_(false) {}
 
 void WebContentsViewAura::SetDelegateForTesting(
     WebContentsViewDelegate* delegate) {
   delegate_.reset(delegate);
 }
 
@@ skipping 24 matching lines @@
 void WebContentsViewAura::EndDrag(blink::WebDragOperationsMask ops) {
   if (!web_contents_)
     return;
 
   aura::Window* window = GetContentNativeView();
   gfx::Point screen_loc = display::Screen::GetScreen()->GetCursorScreenPoint();
   gfx::Point client_loc = screen_loc;
   aura::client::ScreenPositionClient* screen_position_client =
       aura::client::GetScreenPositionClient(window->GetRootWindow());
   if (screen_position_client)
-      screen_position_client->ConvertPointFromScreen(window, &client_loc);
+    screen_position_client->ConvertPointFromScreen(window, &client_loc);
 
-  web_contents_->DragSourceEndedAt(client_loc.x(), client_loc.y(),
-      screen_loc.x(), screen_loc.y(), ops);
+  if (!drag_start_rwh_)
+    return;
+
+  if (drag_start_rwh_.get() ==
+      web_contents_->GetRenderViewHost()->GetWidget()) {
+    web_contents_->DragSourceEndedAt(client_loc.x(), client_loc.x(),
+                                     screen_loc.x(), screen_loc.y(), ops);
+  }
+
+  // TODO(paulmeyer): In the OOPIF case, should |client_loc| be converted to the
+  // coordinates local to |drag_start_rwh_|? See crbug.com/647249.
+  drag_start_rwh_->DragSourceEndedAt(client_loc, screen_loc, ops);
 }
 
 void WebContentsViewAura::InstallOverscrollControllerDelegate(
     RenderWidgetHostViewAura* view) {
   const std::string value = base::CommandLine::ForCurrentProcess()->
       GetSwitchValueASCII(switches::kOverscrollHistoryNavigation);
   if (value == "0") {
     navigation_overlay_.reset();
     return;
   }
@@ skipping 296 matching lines @@
     delegate_->ShowContextMenu(render_frame_host, params);
     // WARNING: we may have been deleted during the call to ShowContextMenu().
   }
 }
 
 void WebContentsViewAura::StartDragging(
     const DropData& drop_data,
     blink::WebDragOperationsMask operations,
     const gfx::ImageSkia& image,
     const gfx::Vector2d& image_offset,
-    const DragEventSourceInfo& event_info) {
+    const DragEventSourceInfo& event_info,
+    RenderWidgetHost* source_rwh) {
   aura::Window* root_window = GetNativeView()->GetRootWindow();
   if (!aura::client::GetDragDropClient(root_window)) {
     web_contents_->SystemDragEnded();
     return;
   }
 
+  drag_start_rwh_ =
+      static_cast<RenderWidgetHostImpl*>(source_rwh)->GetWeakPtr();
+
   ui::TouchSelectionController* selection_controller = GetSelectionController();
   if (selection_controller)
     selection_controller->HideAndDisallowShowingAutomatically();
   std::unique_ptr<ui::OSExchangeData::Provider> provider =
       ui::OSExchangeDataProviderFactory::CreateProvider();
   PrepareDragData(drop_data, provider.get(), web_contents_);
 
   ui::OSExchangeData data(
       std::move(provider));  // takes ownership of |provider|.
 
@@ skipping 202 matching lines @@
   }
 
   web_contents_->GetDelegate()->ContentsMouseEvent(
       web_contents_, display::Screen::GetScreen()->GetCursorScreenPoint(),
       type == ui::ET_MOUSE_MOVED, type == ui::ET_MOUSE_EXITED);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // WebContentsViewAura, aura::client::DragDropDelegate implementation:
 
-// TODO(paulmeyer): The drag-and-drop calls on GetRenderViewHost()->GetWidget()
-// in the following functions will need to be targeted to specific
-// RenderWidgetHosts in order to work with OOPIFs. See crbug.com/647249.
+void WebContentsViewAura::OnDragEntered(const ui::DropTargetEvent& event) {
+  gfx::Point transformed_pt;
+  current_rwh_for_drag_ =
+      web_contents_->GetInputEventRouter()->GetRenderWidgetHostAtPoint(
+          web_contents_->GetRenderViewHost()->GetWidget()->GetView(),
+          event.location(), &transformed_pt)->GetWeakPtr();
+  current_rvh_for_drag_ = web_contents_->GetRenderViewHost();
 
-void WebContentsViewAura::OnDragEntered(const ui::DropTargetEvent& event) {
-  current_rvh_for_drag_ = web_contents_->GetRenderViewHost();
   current_drop_data_.reset(new DropData());
-
   PrepareDropData(current_drop_data_.get(), event.data());
-
-  web_contents_->GetRenderViewHost()->GetWidget()->
-      FilterDropData(current_drop_data_.get());
+  current_rwh_for_drag_->FilterDropData(current_drop_data_.get());
 
   blink::WebDragOperationsMask op = ConvertToWeb(event.source_operations());
 
   // Give the delegate an opportunity to cancel the drag.
   if (web_contents_->GetDelegate() &&
       !web_contents_->GetDelegate()->CanDragEnter(
           web_contents_, *current_drop_data_.get(), op)) {
     current_drop_data_.reset(NULL);
     return;
   }
 
   if (drag_dest_delegate_)
     drag_dest_delegate_->DragInitialize(web_contents_);
 
   gfx::Point screen_pt = display::Screen::GetScreen()->GetCursorScreenPoint();
-  web_contents_->GetRenderViewHost()->GetWidget()->DragTargetDragEnter(
-      *current_drop_data_, event.location(), screen_pt, op,
+  current_rwh_for_drag_->DragTargetDragEnter(
+      *current_drop_data_, transformed_pt, screen_pt, op,
       ConvertAuraEventFlagsToWebInputEventModifiers(event.flags()));
 
   if (drag_dest_delegate_) {
     drag_dest_delegate_->OnReceiveDragData(event.data());
     drag_dest_delegate_->OnDragEnter();
   }
 }
 
 int WebContentsViewAura::OnDragUpdated(const ui::DropTargetEvent& event) {
-  DCHECK(current_rvh_for_drag_);
-  if (current_rvh_for_drag_ != web_contents_->GetRenderViewHost())
+  gfx::Point transformed_pt;
+  RenderWidgetHostImpl* target_rwh =
+      web_contents_->GetInputEventRouter()->GetRenderWidgetHostAtPoint(
+          web_contents_->GetRenderViewHost()->GetWidget()->GetView(),
+          event.location(), &transformed_pt);
+
+  if (target_rwh != current_rwh_for_drag_.get()) {
+    if (current_rwh_for_drag_)
+      current_rwh_for_drag_->DragTargetDragLeave();
     OnDragEntered(event);
+  }
 
   if (!current_drop_data_)
     return ui::DragDropTypes::DRAG_NONE;
 
   blink::WebDragOperationsMask op = ConvertToWeb(event.source_operations());
   gfx::Point screen_pt = event.root_location();
-  web_contents_->GetRenderViewHost()->GetWidget()->DragTargetDragOver(
-      event.location(), screen_pt, op,
+  target_rwh->DragTargetDragOver(
+      transformed_pt, screen_pt, op,
       ConvertAuraEventFlagsToWebInputEventModifiers(event.flags()));
 
   if (drag_dest_delegate_)
     drag_dest_delegate_->OnDragOver();
 
   return ConvertFromWeb(current_drag_op_);
 }
 
 void WebContentsViewAura::OnDragExited() {

[ncarter (slow), 2016/11/16 22:31:23]

Was the old DCHECK(current_rvh_for_drag_) bogus, or did something change
semantically to make it invalid?

[paulmeyer, 2016/11/16 22:44:21]

I wasn't sure how to recreate it using the new weak pointer. It essentially was
checking that current_rvh_for_drag_ had been set before. Now it may have been
set, but will fail the DCHECK if the pointer is invalid.

-  DCHECK(current_rvh_for_drag_);
-  if (current_rvh_for_drag_ != web_contents_->GetRenderViewHost())
+  if (current_rvh_for_drag_ != web_contents_->GetRenderViewHost() ||

[ncarter (slow), 2016/11/16 22:31:23]

Is current_rvh_for_drag_ here to stay, or do later CLs get rid of it? I'm
wondering if 'current_rwh_for_drag_->owner_delegate()' could eventually take its
place; owner_delegate is how the ViewHosts's WidgetHost talks to its ViewHost.
RWHOwnerDelegate to RVH is not a safe cast (RFH also implements
RWHOwnerDelegate), but pointer comparison to an existing RVH ought to work, and
be safer than the 'don't deref me rvh void*' pattern.

Only mentioning this in case you hadn't thought this through. No action needed
in this CL.

[paulmeyer, 2016/11/16 22:44:21]

I think it may go away (I will try to make it go away). If I can't, then I will
replace it with your suggestion in a later CL. :)

+      !current_drop_data_) {
     return;
+  }
 
-  if (!current_drop_data_)
-    return;
+  if (current_rwh_for_drag_) {
+    current_rwh_for_drag_->DragTargetDragLeave();
+    current_rwh_for_drag_.reset();
+  }
 
-  web_contents_->GetRenderViewHost()->GetWidget()->DragTargetDragLeave();
   if (drag_dest_delegate_)
     drag_dest_delegate_->OnDragLeave();
 
   current_drop_data_.reset();
 }
 
 int WebContentsViewAura::OnPerformDrop(const ui::DropTargetEvent& event) {
-  DCHECK(current_rvh_for_drag_);
-  if (current_rvh_for_drag_ != web_contents_->GetRenderViewHost())
+  gfx::Point transformed_pt;
+  RenderWidgetHostImpl* target_rwh =
+      web_contents_->GetInputEventRouter()->GetRenderWidgetHostAtPoint(
+          web_contents_->GetRenderViewHost()->GetWidget()->GetView(),
+          event.location(), &transformed_pt);
+
+  if (target_rwh != current_rwh_for_drag_.get()) {
+    if (current_rwh_for_drag_)
+      current_rwh_for_drag_->DragTargetDragLeave();
     OnDragEntered(event);
+  }
 
   if (!current_drop_data_)
     return ui::DragDropTypes::DRAG_NONE;
 
-  web_contents_->GetRenderViewHost()->GetWidget()->DragTargetDrop(
-      *current_drop_data_, event.location(),
+  target_rwh->DragTargetDrop(
+      *current_drop_data_, transformed_pt,
       display::Screen::GetScreen()->GetCursorScreenPoint(),
       ConvertAuraEventFlagsToWebInputEventModifiers(event.flags()));
   if (drag_dest_delegate_)
     drag_dest_delegate_->OnDrop();
   current_drop_data_.reset();
   return ConvertFromWeb(current_drag_op_);
 }
 
 void WebContentsViewAura::OnWindowVisibilityChanged(aura::Window* window,
                                                     bool visible) {
@@ skipping 15 matching lines @@
                                         bool allow_multiple_selection) {
   NOTIMPLEMENTED() << " show " << items.size() << " menu items";
 }
 
 void WebContentsViewAura::HidePopupMenu() {
   NOTIMPLEMENTED();
 }
 #endif
 
 }  // namespace content