Support dragging texts into Android WebView.

content/browser/web_contents/web_contents_view_android.h

 // 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.
 
 #ifndef CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_ANDROID_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_ANDROID_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "content/browser/renderer_host/render_view_host_delegate_view.h"
 #include "content/browser/web_contents/web_contents_view.h"
 #include "content/public/browser/web_contents_view_delegate.h"
 #include "content/public/common/context_menu_params.h"
+#include "content/public/common/drop_data.h"
 #include "ui/gfx/geometry/rect_f.h"
 
 namespace content {
 class ContentViewCoreImpl;
 class WebContentsImpl;
 
 // Android-specific implementation of the WebContentsView.
 class WebContentsViewAndroid : public WebContentsView,
                                public RenderViewHostDelegateView {
  public:
@@ skipping 44 matching lines @@
   void HidePopupMenu() override;
   void StartDragging(const DropData& drop_data,
                      blink::WebDragOperationsMask allowed_ops,
                      const gfx::ImageSkia& image,
                      const gfx::Vector2d& image_offset,
                      const DragEventSourceInfo& event_info) override;
   void UpdateDragCursor(blink::WebDragOperation operation) override;
   void GotFocus() override;
   void TakeFocus(bool reverse) override;
 
+  void OnDragEntered(const std::vector<DropData::Metadata>& metadata,
+                     std::vector<int> locations);

[dcheng, 2016/06/24 23:07:53]

Let's just pass gfx::Points here. It's a bit more work to convert in the
Java->C++ layer, but it'll make this interface a bit clearer.

Since I haven't done Java<->C++ in a while... would it be even easier to just
plumb these in as individual int params from java? Then we don't need to do the
vector conversion, and we can do a straightforward construction of gfx::Point
from int coords.

[hush (inactive), 2016/06/27 19:01:54]

Done.

+  void OnDragUpdated(std::vector<int> locations);
+  void OnDragExited();
+  void OnPerformDrop(DropData& drop_data, std::vector<int> locations);

[dcheng, 2016/06/24 23:07:53]

Chromium/C++ style doesn't permit mutable reference arguments =/

[hush (inactive), 2016/06/27 19:01:54]

use DropData* instead 

+
  private:
   // The WebContents whose contents we display.
   WebContentsImpl* web_contents_;
 
   // ContentViewCoreImpl is our interface to the view system.
   ContentViewCoreImpl* content_view_core_;
 
   // Interface for extensions to WebContentsView. Used to show the context menu.
   std::unique_ptr<WebContentsViewDelegate> delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsViewAndroid);
 };
 
 } // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_ANDROID_H_