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..6d9dfb97765f80166ff4428aae00b647cf7b8c32 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 +77,12 @@ class WebContentsViewAndroid : public WebContentsView,
   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_;