GuestView: Move Disable Drag and Drop Out to Chrome

chrome/browser/guest_view/guest_view_base.cc

 // Copyright 2014 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 "chrome/browser/guest_view/guest_view_base.h"
 
 #include "base/lazy_instance.h"
+#include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/guest_view/ad_view/ad_view_guest.h"
 #include "chrome/browser/guest_view/guest_view_constants.h"
 #include "chrome/browser/guest_view/guest_view_manager.h"
 #include "chrome/browser/guest_view/web_view/web_view_guest.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/content_settings.h"
+#include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/url_constants.h"
 #include "extensions/browser/event_router.h"
 #include "net/base/escape.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 
 using content::WebContents;
 
 namespace {
 
@@ skipping 191 matching lines @@
     return;
   }
   opener_ = base::WeakPtr<GuestViewBase>();
 }
 
 void GuestViewBase::RegisterDestructionCallback(
     const DestructionCallback& callback) {
   destruction_callback_ = callback;
 }
 
+void GuestViewBase::DidStopLoading(content::RenderViewHost* render_view_host) {
+  // Disable drag-and-drop by default. Derived classes that override this method

[lazyboy, 2014/05/30 00:30:52]

Don't think this is a good way of doing this: "you need to override
DidStopLoading to disable drag and drop"
Also this changes behavior: Every guest view to have dnd enabled instead of just
WebViewGuest.

I think we should add a GuestViewBase::IsDNDEnabled() and check that before
running this script. It's cleaner to understand what's going on that way.

[Fady Samuel, 2014/05/30 01:53:21]

You got the logic reversed. This disables DND by default. Overriding this method
enables it. 

[lazyboy, 2014/05/30 03:11:40]

Yeah I misread.
But my concern is still the same, I'm not concerned about dnd being enabled or
disabled by default; Overriding DidStopLoad magically changing the behavior of
enable/disable dnd would seem very surprising to a Derived class imo.
e.g. XViewGuest gets dnd disabled by default but if they want to do sth on
loadstop and and later override DidStopLoading then dnd gets enabled which
doesn't seem intuitive.

+  // can avoid the script injection, thereby enabling drag-and-drop.
+  const char script[] = "window.addEventListener('dragstart', function() { "
+                        "  window.event.preventDefault(); "
+                        "});";
+  render_view_host->GetMainFrame()->ExecuteJavaScript(
+      base::ASCIIToUTF16(script));
+}
+
 void GuestViewBase::WebContentsDestroyed() {
   delete this;
 }
 
 bool GuestViewBase::ShouldFocusPageAfterCrash() {
   // Focus is managed elsewhere.
   return false;
 }
 
 bool GuestViewBase::PreHandleGestureEvent(content::WebContents* source,
@@ skipping 46 matching lines @@
 
 void GuestViewBase::SendQueuedEvents() {
   if (!attached())
     return;
   while (!pending_events_.empty()) {
     linked_ptr<Event> event_ptr = pending_events_.front();
     pending_events_.pop_front();
     DispatchEvent(event_ptr.release());
   }
 }