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 925f5bbb1213d2943b7c34661550730123a59163..cea19650eb4b7d02f76e5695072336fa5e1e64dd 100644
--- a/content/browser/web_contents/web_contents_view_android.h
+++ b/content/browser/web_contents/web_contents_view_android.h
@@ -12,6 +12,7 @@
 #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 {
@@ -76,6 +77,16 @@ class WebContentsViewAndroid : public WebContentsView,
   void GotFocus() override;
   void TakeFocus(bool reverse) override;
 
+  void OnDragEntered(const std::vector<DropData::Metadata>& metadata,
+                     const gfx::Point& location,
+                     const gfx::Point& screen_location);
+  void OnDragUpdated(const gfx::Point& location,
+                     const gfx::Point& screen_location);
+  void OnDragExited();
+  void OnPerformDrop(DropData* drop_data,
+                     const gfx::Point& location,
+                     const gfx::Point& screen_location);
+
  private:
   // The WebContents whose contents we display.
   WebContentsImpl* web_contents_;