Make drag and drop work on webpage. Also slightly modify drag drop workflow.

content/browser/renderer_host/render_widget_host_view_aura.cc

 // Copyright (c) 2011 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include "base/logging.h"
 #include "content/browser/renderer_host/backing_store_skia.h"
 #include "content/browser/renderer_host/render_widget_host.h"
 #include "content/browser/renderer_host/web_input_event_aura.h"
@@ skipping 456 matching lines @@
     const gfx::Point& point) const {
   return HTCLIENT;
 }
 
 bool RenderWidgetHostViewAura::OnMouseEvent(aura::MouseEvent* event) {
   if (event->type() == ui::ET_MOUSEWHEEL)
     host_->ForwardWheelEvent(content::MakeWebMouseWheelEvent(event));
   else if (CanRendererHandleEvent(event->native_event()))
     host_->ForwardMouseEvent(content::MakeWebMouseEvent(event));
 
+  switch (event->type()) {
+    case ui::ET_MOUSE_PRESSED:
+      window_->SetCapture();
+      break;
+    case ui::ET_MOUSE_RELEASED:
+      window_->ReleaseCapture();
+      break;
+    default:
+      break;
+  }
+
   // Return true so that we receive released/drag events.
   return true;
 }
 
 ui::TouchStatus RenderWidgetHostViewAura::OnTouchEvent(
     aura::TouchEvent* event) {
   // Update the touch event first.
   WebKit::WebTouchPoint* point = content::UpdateWebTouchEvent(event,
       &touch_event_);
 
@@ skipping 83 matching lines @@
 // static
 void RenderWidgetHostView::GetDefaultScreenInfo(
     WebKit::WebScreenInfo* results) {
   const gfx::Size size = gfx::Screen::GetPrimaryMonitorSize();
   results->rect = WebKit::WebRect(0, 0, size.width(), size.height());
   results->availableRect = results->rect;
   // TODO(derat): Don't hardcode this?
   results->depth = 24;
   results->depthPerComponent = 8;
 }