Support dragging texts into Android WebView.

content/browser/web_contents/web_contents_view_android.cc

Index: content/browser/web_contents/web_contents_view_android.cc
diff --git a/content/browser/web_contents/web_contents_view_android.cc b/content/browser/web_contents/web_contents_view_android.cc
index 0716d13d2fb2ae9053899b12397de5234c4c44ea..38d8778bf44a8f1a17a83557bcf2da5ae5952f30 100644
--- a/content/browser/web_contents/web_contents_view_android.cc
+++ b/content/browser/web_contents/web_contents_view_android.cc
@@ -5,6 +5,8 @@
 #include "content/browser/web_contents/web_contents_view_android.h"
 
 #include "base/logging.h"
+#include "base/pickle.h"
+#include "base/strings/utf_string_conversions.h"
 #include "content/browser/android/content_view_core_impl.h"
 #include "content/browser/frame_host/interstitial_page_impl.h"
 #include "content/browser/renderer_host/render_widget_host_view_android.h"
@@ -13,8 +15,27 @@
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/web_contents_delegate.h"
+#include "content/public/common/drop_data.h"
+#include "ui/base/dragdrop/drag_drop_types.h"
+#include "ui/base/dragdrop/drop_target_event.h"
+#include "ui/base/dragdrop/os_exchange_data.h"
 
 namespace content {
+
+namespace {
+
+void PrepareDropData(DropData* drop_data, const ui::OSExchangeData& data) {
+  // TODO(hush): support dragging files here.
+  drop_data->did_originate_from_renderer = data.DidOriginateFromRenderer();
+
+  base::string16 plain_text;
+  bool has_string = data.GetString(&plain_text);
+  if (has_string)
+    drop_data->text = base::NullableString16(plain_text, false);
+}
+
+}  // namespace
+
 WebContentsView* CreateWebContentsView(
     WebContentsImpl* web_contents,
     WebContentsViewDelegate* delegate,
@@ -199,6 +220,36 @@ void WebContentsViewAndroid::UpdateDragCursor(blink::WebDragOperation op) {
   NOTIMPLEMENTED();
 }
 
+void WebContentsViewAndroid::OnDragEntered(const ui::DropTargetEvent& event) {
+  current_drop_data_.reset(new DropData());
+  PrepareDropData(current_drop_data_.get(), event.data());
+
+  web_contents_->GetRenderViewHost()->DragTargetDragEnter(
+      *current_drop_data_.get(), event.location(), event.root_location(),
+      blink::WebDragOperationCopy, 0);
+}
+
+void WebContentsViewAndroid::OnDragUpdated(const ui::DropTargetEvent& event) {
+  if (!current_drop_data_)
+    return;
+
+  web_contents_->GetRenderViewHost()->DragTargetDragOver(
+      event.location(), event.root_location(), blink::WebDragOperationCopy, 0);
+}
+
+void WebContentsViewAndroid::OnDragExited() {
+  web_contents_->GetRenderViewHost()->DragTargetDragLeave();
+  current_drop_data_.reset();
+}
+
+void WebContentsViewAndroid::OnPerformDrop(const ui::DropTargetEvent& event) {
+  current_drop_data_.reset(new DropData());
+  PrepareDropData(current_drop_data_.get(), event.data());
+
+  web_contents_->GetRenderViewHost()->DragTargetDropWithData(
+      *current_drop_data_.get(), event.location(), event.root_location(), 0);
+}
+
 void WebContentsViewAndroid::GotFocus() {
   // This is only used in the views FocusManager stuff but it bleeds through
   // all subclasses. http://crbug.com/21875