Support dragging texts into Android WebView.

content/browser/web_contents/web_contents_view_android.h

Index: content/browser/web_contents/web_contents_view_android.h
diff --git a/content/browser/web_contents/web_contents_view_android.h b/content/browser/web_contents/web_contents_view_android.h
index 6b135dc214cd0b89da51b6180a39a5e5a574d8aa..8712831259aac4f2619cad6e015c41ac96c76882 100644
--- a/content/browser/web_contents/web_contents_view_android.h
+++ b/content/browser/web_contents/web_contents_view_android.h
@@ -11,8 +11,13 @@
 #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 ui {
+class DropTargetEvent;
+}
+
 namespace content {
 class ContentViewCoreImpl;
 class WebContentsImpl;
@@ -75,10 +80,17 @@ class WebContentsViewAndroid : public WebContentsView,
   void GotFocus() override;
   void TakeFocus(bool reverse) override;
 
+  void OnDragEntered(const ui::DropTargetEvent& event);
+  void OnDragUpdated(const ui::DropTargetEvent& event);
+  void OnDragExited();
+  void OnPerformDrop(const ui::DropTargetEvent& event);
+
  private:
   // The WebContents whose contents we display.
   WebContentsImpl* web_contents_;
 
+  scoped_ptr<DropData> current_drop_data_;
+
   // ContentViewCoreImpl is our interface to the view system.
   ContentViewCoreImpl* content_view_core_;