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

content/browser/web_contents/web_drag_dest_mac.mm

 // 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.
 
 #import "content/browser/web_contents/web_drag_dest_mac.h"
 
 #import <Carbon/Carbon.h>
 
 #include "base/strings/sys_string_conversions.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/web_contents/web_contents_impl.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/browser/web_drag_dest_delegate.h"
 #include "content/public/common/drop_data.h"
 #include "third_party/WebKit/public/platform/WebInputEvent.h"
 #import "third_party/mozilla/NSPasteboard+Utils.h"
 #include "ui/base/clipboard/custom_data_helper.h"
 #include "ui/base/cocoa/cocoa_base_utils.h"
 #import "ui/base/dragdrop/cocoa_dnd_util.h"
 #include "ui/base/window_open_disposition.h"
+#include "ui/gfx/geometry/point.h"
 
 using blink::WebDragOperationsMask;
 using content::DropData;
 using content::OpenURLParams;
 using content::Referrer;
 using content::WebContentsImpl;
 
 namespace {
 
 int GetModifierFlags() {
@@ skipping 87 matching lines @@
 
 // Messages to send during the tracking of a drag, usually upon receiving
 // calls from the view system. Communicates the drag messages to WebCore.
 
 - (NSDragOperation)draggingEntered:(id<NSDraggingInfo>)info
                               view:(NSView*)view {
   // Save off the RVH so we can tell if it changes during a drag. If it does,
   // we need to send a new enter message in draggingUpdated:.
   currentRVH_ = webContents_->GetRenderViewHost();
 
+  // Create the appropriate mouse locations for WebCore. The draggingLocation
+  // is in window coordinates. Both need to be flipped.
+  NSPoint windowPoint = [info draggingLocation];
+  NSPoint viewPoint = [self flipWindowPointToView:windowPoint view:view];
+  NSPoint screenPoint = [self flipWindowPointToScreen:windowPoint view:view];

[dcheng, 2016/11/17 19:59:02]

Can these three lines be moved into the helper as well? We seem to be doing the
same transforms.

[paulmeyer, 2016/11/17 20:46:43]

Maybe... though I wasn't sure exactly how it should be done, so I'd rather
continue any of that cleanup in a separate CL because I want to get this landed
soon.

All of these lines were already in all of these functions before my change as
well.

+  gfx::Point transformedPt;
+  currentRWHForDrag_ =
+      [self GetRenderWidgetHostAtPoint:viewPoint transformedPt:&transformedPt]
+          ->GetWeakPtr();
+
   // Fill out a DropData from pasteboard.
   std::unique_ptr<DropData> dropData;
   dropData.reset(new DropData());
   [self populateDropData:dropData.get()
              fromPasteboard:[info draggingPasteboard]];
-  // TODO(paulmeyer): This will need to target the correct specific
-  // RenderWidgetHost to work with OOPIFs. See crbug.com/647249.
-  currentRVH_->GetWidget()->FilterDropData(dropData.get());
+  currentRWHForDrag_->FilterDropData(dropData.get());

[dcheng, 2016/11/17 19:59:02]

I think this still needs a TODO: it means we pull the data from the pasteboard
multiple times per drag. Ideally, we'd only do it once, and filter it as
appropriate.

[paulmeyer, 2016/11/17 20:46:43]

Added TODO.

 
   NSDragOperation mask = [info draggingSourceOperationMask];
 
   // Give the delegate an opportunity to cancel the drag.
   canceled_ = !webContents_->GetDelegate()->CanDragEnter(
       webContents_,
       *dropData,
       static_cast<WebDragOperationsMask>(mask));
   if (canceled_)
     return NSDragOperationNone;
 
   if ([self onlyAllowsNavigation]) {
     if ([[info draggingPasteboard] containsURLDataConvertingTextToURL:YES])
       return NSDragOperationCopy;
     return NSDragOperationNone;
   }
 
   if (delegate_) {
     delegate_->DragInitialize(webContents_);
     delegate_->OnDragEnter();
   }
 
   dropData_.swap(dropData);
 
-  // Create the appropriate mouse locations for WebCore. The draggingLocation
-  // is in window coordinates. Both need to be flipped.
-  NSPoint windowPoint = [info draggingLocation];
-  NSPoint viewPoint = [self flipWindowPointToView:windowPoint view:view];
-  NSPoint screenPoint = [self flipWindowPointToScreen:windowPoint view:view];
-  // TODO(paulmeyer): This will need to target the correct specific
-  // RenderWidgetHost to work with OOPIFs. See crbug.com/647249.
-  webContents_->GetRenderViewHost()->GetWidget()->DragTargetDragEnter(
-      *dropData_,
-      gfx::Point(viewPoint.x, viewPoint.y),
-      gfx::Point(screenPoint.x, screenPoint.y),
-      static_cast<WebDragOperationsMask>(mask),
-      GetModifierFlags());
+  currentRWHForDrag_->DragTargetDragEnter(
+      *dropData_, transformedPt, gfx::Point(screenPoint.x, screenPoint.y),
+      static_cast<WebDragOperationsMask>(mask), GetModifierFlags());
 
   // We won't know the true operation (whether the drag is allowed) until we
   // hear back from the renderer. For now, be optimistic:
   currentOperation_ = NSDragOperationCopy;
   return currentOperation_;
 }
 
 - (void)draggingExited:(id<NSDraggingInfo>)info {
   DCHECK(currentRVH_);
   if (currentRVH_ != webContents_->GetRenderViewHost())
     return;
 
   if (canceled_)
     return;
 
   if ([self onlyAllowsNavigation])
     return;
 
   if (delegate_)
     delegate_->OnDragLeave();
 
-  // TODO(paulmeyer): This will need to target the correct specific
-  // RenderWidgetHost to work with OOPIFs. See crbug.com/647249.
-  webContents_->GetRenderViewHost()->GetWidget()->DragTargetDragLeave();
+  if (currentRWHForDrag_) {
+    currentRWHForDrag_->DragTargetDragLeave();
+    currentRWHForDrag_.reset();
+  }
   dropData_.reset();
 }
 
 - (NSDragOperation)draggingUpdated:(id<NSDraggingInfo>)info
                               view:(NSView*)view {
-  DCHECK(currentRVH_);
-  if (currentRVH_ != webContents_->GetRenderViewHost())
+  // Create the appropriate mouse locations for WebCore. The draggingLocation
+  // is in window coordinates. Both need to be flipped.
+  NSPoint windowPoint = [info draggingLocation];
+  NSPoint viewPoint = [self flipWindowPointToView:windowPoint view:view];
+  NSPoint screenPoint = [self flipWindowPointToScreen:windowPoint view:view];
+  gfx::Point transformedPt;
+  content::RenderWidgetHostImpl* targetRWH =
+      [self GetRenderWidgetHostAtPoint:viewPoint transformedPt:&transformedPt];
+
+  if (targetRWH != currentRWHForDrag_.get()) {
+    if (currentRWHForDrag_)
+      currentRWHForDrag_->DragTargetDragLeave();
     [self draggingEntered:info view:view];

[dcheng, 2016/11/17 19:59:02]

The various delegates for dragging can now be invoked multiple times per drag,
without the drag ever leaving the window. I'm concerned that this will confuse
things: for example, we potentially call delegate_->DragInitialize(),
delegate_->OnDragEnter(), and WebContentsDelegate::CanDragEnter() multiple times
without ever leaving the content area.

It might be OK to land this as-is, but I think it needs a TODO to fix.

[paulmeyer, 2016/11/17 20:46:43]

Added TODO.

+  }
 
   if (canceled_)
     return NSDragOperationNone;
 
   if ([self onlyAllowsNavigation]) {
     if ([[info draggingPasteboard] containsURLDataConvertingTextToURL:YES])
       return NSDragOperationCopy;
     return NSDragOperationNone;
   }
 
-  // Create the appropriate mouse locations for WebCore. The draggingLocation
-  // is in window coordinates.
-  NSPoint windowPoint = [info draggingLocation];
-  NSPoint viewPoint = [self flipWindowPointToView:windowPoint view:view];
-  NSPoint screenPoint = [self flipWindowPointToScreen:windowPoint view:view];
   NSDragOperation mask = [info draggingSourceOperationMask];
-  // TODO(paulmeyer): This will need to target the correct specific
-  // RenderWidgetHost to work with OOPIFs. See crbug.com/647249.
-  webContents_->GetRenderViewHost()->GetWidget()->DragTargetDragOver(
-      gfx::Point(viewPoint.x, viewPoint.y),
-      gfx::Point(screenPoint.x, screenPoint.y),
-      static_cast<WebDragOperationsMask>(mask),
-      GetModifierFlags());
+  targetRWH->DragTargetDragOver(
+      transformedPt, gfx::Point(screenPoint.x, screenPoint.y),
+      static_cast<WebDragOperationsMask>(mask), GetModifierFlags());
 
   if (delegate_)
     delegate_->OnDragOver();
 
   return currentOperation_;
 }
 
 - (BOOL)performDragOperation:(id<NSDraggingInfo>)info
                               view:(NSView*)view {
-  if (currentRVH_ != webContents_->GetRenderViewHost())
+  // Create the appropriate mouse locations for WebCore. The draggingLocation
+  // is in window coordinates. Both need to be flipped.
+  NSPoint windowPoint = [info draggingLocation];
+  NSPoint viewPoint = [self flipWindowPointToView:windowPoint view:view];
+  NSPoint screenPoint = [self flipWindowPointToScreen:windowPoint view:view];
+  gfx::Point transformedPt;
+  content::RenderWidgetHostImpl* targetRWH =
+      [self GetRenderWidgetHostAtPoint:viewPoint transformedPt:&transformedPt];
+
+  if (targetRWH != currentRWHForDrag_.get()) {
+    if (currentRWHForDrag_)
+      currentRWHForDrag_->DragTargetDragLeave();
     [self draggingEntered:info view:view];
+  }
 
   // Check if we only allow navigation and navigate to a url on the pasteboard.
   if ([self onlyAllowsNavigation]) {
     NSPasteboard* pboard = [info draggingPasteboard];
     if ([pboard containsURLDataConvertingTextToURL:YES]) {
       GURL url;
       ui::PopulateURLAndTitleFromPasteboard(&url, NULL, pboard, YES);
       webContents_->OpenURL(
           OpenURLParams(url, Referrer(), WindowOpenDisposition::CURRENT_TAB,
                         ui::PAGE_TRANSITION_AUTO_BOOKMARK, false));
       return YES;
     } else {
       return NO;
     }
   }
 
   if (delegate_)
     delegate_->OnDrop();
 
   currentRVH_ = NULL;
 
-  // Create the appropriate mouse locations for WebCore. The draggingLocation
-  // is in window coordinates. Both need to be flipped.
-  NSPoint windowPoint = [info draggingLocation];
-  NSPoint viewPoint = [self flipWindowPointToView:windowPoint view:view];
-  NSPoint screenPoint = [self flipWindowPointToScreen:windowPoint view:view];
-  // TODO(paulmeyer): This will need to target the correct specific
-  // RenderWidgetHost to work with OOPIFs. See crbug.com/647249.
-  webContents_->GetRenderViewHost()->GetWidget()->DragTargetDrop(
-      *dropData_, gfx::Point(viewPoint.x, viewPoint.y),
-      gfx::Point(screenPoint.x, screenPoint.y), GetModifierFlags());
+  targetRWH->DragTargetDrop(*dropData_, transformedPt,
+                            gfx::Point(screenPoint.x, screenPoint.y),
+                            GetModifierFlags());
 
   dropData_.reset();
 
   return YES;
 }
 
+- (content::RenderWidgetHostImpl*)
+GetRenderWidgetHostAtPoint:(const NSPoint&)viewPoint
+             transformedPt:(gfx::Point*)transformedPt {
+  return webContents_->GetInputEventRouter()->GetRenderWidgetHostAtPoint(
+      webContents_->GetRenderViewHost()->GetWidget()->GetView(),
+      gfx::Point(viewPoint.x, viewPoint.y), transformedPt);
+}
+
 // Given |data|, which should not be nil, fill it in using the contents of the
 // given pasteboard. The types handled by this method should be kept in sync
 // with [WebContentsViewCocoa registerDragTypes].
 - (void)populateDropData:(DropData*)data
           fromPasteboard:(NSPasteboard*)pboard {
   DCHECK(data);
   DCHECK(pboard);
   NSArray* types = [pboard types];
 
   data->did_originate_from_renderer =
@@ skipping 47 matching lines @@
   // Get custom MIME data.
   if ([types containsObject:ui::kWebCustomDataPboardType]) {
     NSData* customData = [pboard dataForType:ui::kWebCustomDataPboardType];
     ui::ReadCustomDataIntoMap([customData bytes],
                               [customData length],
                               &data->custom_data);
   }
 }
 
 @end