Do not allow URL drops on app windows to cause a navigation away

from the currently loaded site.  We are careful in this patch to
continue to allow dropping URLs in text fields within the app
window, and behavior for normal browser windows remains as
before.

There is a slight glitch when dragging a to an app window on the
border of the window.  Even though it is very brief, it is still
disturbing.

BUG=7171
TEST=Open Chrome (1), load google.com.  Open Chrome (2), load
yahoo.com.  Drag a link from 1 to 2 and a link from 2 to 1 (both
allowed).  Create an app shortcut from 1, drag a link from 1 to
2 (allowed) and a link from 2 to 1 (denied).  Verify that link
scan be dragged to the omnibox and to text fields.

Patch by Chase Phillips <chase@chromium.org> via
http://codereview.chromium.org/119298

Review URL: http://codereview.chromium.org/121003


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18100 0039d316-1c4b-4281-b951-d872f2087c98

18 files changed, 132 insertions, 9 deletions

diff --git a/chrome/browser/browser.cc b/chrome/browser/browser.cc
index 3f6b024..fe267cb 100644
--- a/chrome/browser/browser.cc
+++ b/chrome/browser/browser.cc
@@ -201,6 +201,8 @@ Browser::Browser(Type type, Profile* profile)
   // Trim browser memory on idle for low & medium memory models.
   if (g_browser_process->memory_model() < BrowserProcess::HIGH_MEMORY_MODEL)
     idle_task_->Start();
+
+  renderer_preferences_.can_accept_load_drops = (this->type() == TYPE_NORMAL);
 }
 
 Browser::~Browser() {
@@ -321,6 +323,8 @@ void Browser::OpenApplicationWindow(Profile* profile, const GURL& url) {
   Browser* browser = Browser::CreateForApp(app_name, profile, false);
   browser->AddTabWithURL(url, GURL(), PageTransition::START_PAGE, true, -1,
                          false, NULL);
+  browser->GetSelectedTabContents()->render_view_host()->SetRendererPrefs(
+      browser->GetSelectedTabContents()->delegate()->GetRendererPrefs());
   browser->window()->Show();
   // TODO(jcampan): http://crbug.com/8123 we should not need to set the initial
   //                focus explicitly.
@@ -1859,6 +1863,8 @@ void Browser::ConvertContentsToApplication(TabContents* contents) {
   DetachContents(contents);
   Browser* browser = Browser::CreateForApp(app_name, profile_, false);
   browser->tabstrip_model()->AppendTabContents(contents, true);
+  browser->GetSelectedTabContents()->render_view_host()->SetRendererPrefs(
+      browser->GetSelectedTabContents()->delegate()->GetRendererPrefs());
   browser->window()->Show();
 }
 
diff --git a/chrome/browser/renderer_host/render_view_host.cc b/chrome/browser/renderer_host/render_view_host.cc
index 63ea4ae..5e4fd06 100644
--- a/chrome/browser/renderer_host/render_view_host.cc
+++ b/chrome/browser/renderer_host/render_view_host.cc
@@ -181,6 +181,7 @@ bool RenderViewHost::CreateRenderView() {
 
   Send(new ViewMsg_New(GetNativeViewId(),
                        modal_dialog_event,
+                       delegate_->GetRendererPrefs(),
                        delegate_->GetWebkitPrefs(),
                        routing_id()));
 
@@ -202,6 +203,11 @@ bool RenderViewHost::IsRenderViewLive() const {
   return process()->channel() && renderer_initialized_;
 }
 
+void RenderViewHost::SetRendererPrefs(
+    const RendererPreferences& renderer_prefs) {
+  Send(new ViewMsg_SetRendererPrefs(routing_id(), renderer_prefs));
+}
+
 void RenderViewHost::NavigateToEntry(const NavigationEntry& entry,
                                      bool is_reload) {
   ViewMsg_Navigate_Params params;
diff --git a/chrome/browser/renderer_host/render_view_host.h b/chrome/browser/renderer_host/render_view_host.h
index 14c03c1..efe3b39 100644
--- a/chrome/browser/renderer_host/render_view_host.h
+++ b/chrome/browser/renderer_host/render_view_host.h
@@ -102,6 +102,8 @@ class RenderViewHost : public RenderWidgetHost {
   // Returns true if the RenderView is active and has not crashed.
   virtual bool IsRenderViewLive() const;
 
+  virtual void SetRendererPrefs(const RendererPreferences& renderer_prefs);
+
   // Load the specified entry, optionally reloading.
   virtual void NavigateToEntry(const NavigationEntry& entry, bool is_reload);
 
diff --git a/chrome/browser/renderer_host/render_view_host_delegate.h b/chrome/browser/renderer_host/render_view_host_delegate.h
index c2488b2..abfaf86 100644
--- a/chrome/browser/renderer_host/render_view_host_delegate.h
+++ b/chrome/browser/renderer_host/render_view_host_delegate.h
@@ -12,6 +12,7 @@
 #include "base/file_path.h"
 #include "base/gfx/rect.h"
 #include "base/logging.h"
+#include "chrome/browser/renderer_preferences.h"
 #include "chrome/common/native_web_keyboard_event.h"
 #include "net/base/load_states.h"
 #include "webkit/glue/password_form.h"
@@ -366,6 +367,12 @@ class RenderViewHostDelegate {
     return GURL();
   }
 
+  // Return a dummy RendererPreferences object that will be used by the renderer
+  // associated with the owning RenderViewHost.
+  virtual RendererPreferences GetRendererPrefs() const {
+    return RendererPreferences();
+  }
+
   // Returns a WebPreferences object that will be used by the renderer
   // associated with the owning render view host.
   virtual WebPreferences GetWebkitPrefs() {
diff --git a/chrome/browser/renderer_preferences.h b/chrome/browser/renderer_preferences.h
new file mode 100644
index 0000000..0a4b34f
--- /dev/null
+++ b/chrome/browser/renderer_preferences.h
@@ -0,0 +1,25 @@
+// Copyright (c) 2006-2008 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.
+//
+// A struct for managing browser's settings that apply to the renderer or its
+// webview.  These differ from WebPreferences since they apply to Chromium's
+// glue layer rather than applying to just WebKit.
+//
+// Adding new values to this class probably involves updating
+// common/render_messages.h, browser/browser.cc, etc.
+
+#ifndef CHROME_BROWSER_RENDERER_PREFERENCES_H_
+#define CHROME_BROWSER_RENDERER_PREFERENCES_H_
+
+struct RendererPreferences {
+  // Whether the renderer's current browser context accept drops from the OS
+  // that result in navigations away from the current page.
+  bool can_accept_load_drops;
+
+  RendererPreferences()
+      : can_accept_load_drops(true) {
+  }
+};
+
+#endif  // CHROME_BROWSER_RENDERER_PREFERENCES_H_
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index ad09bf6..297ed28 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -1482,6 +1482,13 @@ RenderViewHostDelegate::Save* TabContents::GetSaveDelegate() const {
   return save_package_.get();  // May be NULL, but we can return NULL.
 }
 
+RendererPreferences TabContents::GetRendererPrefs() const {
+  if (delegate())
+    return delegate()->GetRendererPrefs();
+  else
+    return RendererPreferences();
+}
+
 ExtensionFunctionDispatcher* TabContents::CreateExtensionFunctionDispatcher(
     RenderViewHost* render_view_host,
     const std::string& extension_id) {
diff --git a/chrome/browser/tab_contents/tab_contents.h b/chrome/browser/tab_contents/tab_contents.h
index 92a67bc..8bb35c9 100644
--- a/chrome/browser/tab_contents/tab_contents.h
+++ b/chrome/browser/tab_contents/tab_contents.h
@@ -23,6 +23,7 @@
 #include "chrome/browser/find_notification_details.h"
 #include "chrome/browser/shell_dialogs.h"
 #include "chrome/browser/renderer_host/render_view_host_delegate.h"
+#include "chrome/browser/renderer_preferences.h"
 #include "chrome/browser/tab_contents/constrained_window.h"
 #include "chrome/browser/tab_contents/infobar_delegate.h"
 #include "chrome/browser/tab_contents/navigation_controller.h"
@@ -710,6 +711,7 @@ class TabContents : public PageNavigator,
 
   // RenderViewHostDelegate ----------------------------------------------------
 
+  virtual RendererPreferences GetRendererPrefs() const;
   virtual RenderViewHostDelegate::View* GetViewDelegate() const;
   virtual RenderViewHostDelegate::Save* GetSaveDelegate() const;
   virtual ExtensionFunctionDispatcher *CreateExtensionFunctionDispatcher(
diff --git a/chrome/browser/tab_contents/tab_contents_delegate.h b/chrome/browser/tab_contents/tab_contents_delegate.h
index da5bd60..43f5cc4 100644
--- a/chrome/browser/tab_contents/tab_contents_delegate.h
+++ b/chrome/browser/tab_contents/tab_contents_delegate.h
@@ -8,6 +8,7 @@
 #include "base/basictypes.h"
 #include "base/gfx/native_widget_types.h"
 #include "base/gfx/rect.h"
+#include "chrome/browser/renderer_preferences.h"
 #include "chrome/common/page_transition_types.h"
 #include "webkit/glue/window_open_disposition.h"
 
@@ -179,8 +180,12 @@ class TabContentsDelegate {
   virtual void OnStartDownload(DownloadItem* download) {
   }
 
+  // Returns the renderer's current preferences settings.
+  RendererPreferences GetRendererPrefs() const { return renderer_preferences_; }
+
  protected:
   ~TabContentsDelegate() {}
+  RendererPreferences renderer_preferences_;
 
 };
 
diff --git a/chrome/chrome.gyp b/chrome/chrome.gyp
index a6953cd..d9ea3ea 100644
--- a/chrome/chrome.gyp
+++ b/chrome/chrome.gyp
@@ -1249,6 +1249,7 @@
         'browser/renderer_host/sync_resource_handler.h',
         'browser/renderer_host/web_cache_manager.cc',
         'browser/renderer_host/web_cache_manager.h',
+        'browser/renderer_preferences.h',
         'browser/rlz/rlz.cc',
         'browser/rlz/rlz.h',
         'browser/safe_browsing/bloom_filter.cc',
@@ -2087,6 +2088,7 @@
         # But app/ is the wrong directory for them.
         # Better is to remove the dep of *_tests on renderer, but in the
         # short term I'd like the build to work.
+        'browser/renderer_preferences.h',
         'renderer/automation/dom_automation_controller.cc',
         'renderer/automation/dom_automation_controller.h',
         'renderer/extensions/bindings_utils.cc',
diff --git a/chrome/common/render_messages.h b/chrome/common/render_messages.h
index 50749cb..57cdcc8 100644
--- a/chrome/common/render_messages.h
+++ b/chrome/common/render_messages.h
@@ -14,6 +14,7 @@
 #include "base/ref_counted.h"
 #include "base/shared_memory.h"
 #include "chrome/browser/renderer_host/resource_handler.h"
+#include "chrome/browser/renderer_preferences.h"
 #include "chrome/common/filter_policy.h"
 #include "chrome/common/ipc_message_utils.h"
 #include "chrome/common/modal_dialog_event.h"
@@ -1507,6 +1508,21 @@ struct ParamTraits<ViewHostMsg_DidPrintPage_Params> {
   }
 };
 
+// Traits for RendererPreferences structure to pack/unpack.
+template <>
+struct ParamTraits<RendererPreferences> {
+  typedef RendererPreferences param_type;
+  static void Write(Message* m, const param_type& p) {
+    WriteParam(m, p.can_accept_load_drops);
+  }
+  static bool Read(const Message* m, void** iter, param_type* p) {
+    return ReadParam(m, iter, &p->can_accept_load_drops);
+  }
+  static void Log(const param_type& p, std::wstring* l) {
+    l->append(L"<RendererPreferences>");
+  }
+};
+
 // Traits for WebPreferences structure to pack/unpack.
 template <>
 struct ParamTraits<WebPreferences> {
diff --git a/chrome/common/render_messages_internal.h b/chrome/common/render_messages_internal.h
index d6d56bf..7984ebf 100644
--- a/chrome/common/render_messages_internal.h
+++ b/chrome/common/render_messages_internal.h
@@ -41,9 +41,10 @@ IPC_BEGIN_MESSAGES(View)
   // Tells the renderer to create a new view.
   // This message is slightly different, the view it takes is the view to
   // create, the message itself is sent as a non-view control message.
-  IPC_MESSAGE_CONTROL4(ViewMsg_New,
+  IPC_MESSAGE_CONTROL5(ViewMsg_New,
                        gfx::NativeViewId, /* parent window */
                        ModalDialogEvent, /* model dialog box event */
+                       RendererPreferences,
                        WebPreferences,
                        int32 /* view id */)
 
@@ -59,6 +60,10 @@ IPC_BEGIN_MESSAGES(View)
   IPC_MESSAGE_ROUTED1(ViewMsg_CreatingNew_ACK,
                       gfx::NativeViewId /* parent_hwnd */)
 
+  // Sends updated preferences to the renderer.
+  IPC_MESSAGE_ROUTED1(ViewMsg_SetRendererPrefs,
+                      RendererPreferences)
+
   // Tells the render view to close.
   IPC_MESSAGE_ROUTED0(ViewMsg_Close)
 
diff --git a/chrome/renderer/render_thread.cc b/chrome/renderer/render_thread.cc
index 3a0e739..2b919ac 100644
--- a/chrome/renderer/render_thread.cc
+++ b/chrome/renderer/render_thread.cc
@@ -10,6 +10,7 @@
 #include "base/command_line.h"
 #include "base/shared_memory.h"
 #include "base/stats_table.h"
+#include "chrome/browser/renderer_preferences.h"
 #include "chrome/common/app_cache/app_cache_context_impl.h"
 #include "chrome/common/app_cache/app_cache_dispatcher.h"
 #include "chrome/common/chrome_switches.h"
@@ -241,6 +242,7 @@ void RenderThread::OnSetNextPageID(int32 next_page_id) {
 
 void RenderThread::OnCreateNewView(gfx::NativeViewId parent_hwnd,
                                    ModalDialogEvent modal_dialog_event,
+                                   const RendererPreferences& renderer_prefs,
                                    const WebPreferences& webkit_prefs,
                                    int32 view_id) {
   EnsureWebKitInitialized();
@@ -256,8 +258,8 @@ void RenderThread::OnCreateNewView(gfx::NativeViewId parent_hwnd,
   // TODO(darin): once we have a RenderThread per RenderView, this will need to
   // change to assert that we are not creating more than one view.
   RenderView::Create(
-      this, parent_hwnd, waitable_event, MSG_ROUTING_NONE, webkit_prefs,
-      new SharedRenderViewCounter(0), view_id);
+      this, parent_hwnd, waitable_event, MSG_ROUTING_NONE, renderer_prefs,
+      webkit_prefs, new SharedRenderViewCounter(0), view_id);
 }
 
 void RenderThread::OnSetCacheCapacities(size_t min_dead_capacity,
diff --git a/chrome/renderer/render_thread.h b/chrome/renderer/render_thread.h
index 7935a32..36cef3a 100644
--- a/chrome/renderer/render_thread.h
+++ b/chrome/renderer/render_thread.h
@@ -12,6 +12,7 @@
 #include "base/shared_memory.h"
 #include "base/task.h"
 #include "build/build_config.h"
+#include "chrome/browser/renderer_preferences.h"
 #include "chrome/common/child_thread.h"
 #include "chrome/renderer/renderer_histogram_snapshots.h"
 
@@ -122,6 +123,7 @@ class RenderThread : public RenderThreadBase,
   void OnSetNextPageID(int32 next_page_id);
   void OnCreateNewView(gfx::NativeViewId parent_hwnd,
                        ModalDialogEvent modal_dialog_event,
+                       const RendererPreferences& renderer_prefs,
                        const WebPreferences& webkit_prefs,
                        int32 view_id);
   void OnTransferBitmap(const SkBitmap& bitmap, int resource_id);
diff --git a/chrome/renderer/render_view.cc b/chrome/renderer/render_view.cc
index d5db96e..13876ec 100644
--- a/chrome/renderer/render_view.cc
+++ b/chrome/renderer/render_view.cc
@@ -21,6 +21,7 @@
 #include "base/string_piece.h"
 #include "base/string_util.h"
 #include "build/build_config.h"
+#include "chrome/browser/renderer_preferences.h"
 #include "chrome/common/bindings_policy.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_constants.h"
@@ -193,7 +194,8 @@ RenderView::RenderView(RenderThreadBase* render_thread)
       popup_notification_visible_(false),
       delay_seconds_for_form_state_sync_(kDefaultDelaySecondsForFormStateSync),
       preferred_width_(0),
-      send_preferred_width_changes_(false) {
+      send_preferred_width_changes_(false),
+      renderer_preferences_(*(new RendererPreferences)) {
 }
 
 RenderView::~RenderView() {
@@ -217,6 +219,7 @@ RenderView* RenderView::Create(
     gfx::NativeViewId parent_hwnd,
     base::WaitableEvent* modal_dialog_event,
     int32 opener_id,
+    const RendererPreferences& renderer_prefs,
     const WebPreferences& webkit_prefs,
     SharedRenderViewCounter* counter,
     int32 routing_id) {
@@ -225,6 +228,7 @@ RenderView* RenderView::Create(
   view->Init(parent_hwnd,
              modal_dialog_event,
              opener_id,
+             renderer_prefs,
              webkit_prefs,
              counter,
              routing_id);  // adds reference
@@ -265,6 +269,7 @@ void RenderView::JSOutOfMemory() {
 void RenderView::Init(gfx::NativeViewId parent_hwnd,
                       base::WaitableEvent* modal_dialog_event,
                       int32 opener_id,
+                      const RendererPreferences& renderer_prefs,
                       const WebPreferences& webkit_prefs,
                       SharedRenderViewCounter* counter,
                       int32 routing_id) {
@@ -282,6 +287,8 @@ void RenderView::Init(gfx::NativeViewId parent_hwnd,
     decrement_shared_popup_at_destruction_ = false;
   }
 
+  OnSetRendererPrefs(renderer_prefs);
+
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   bool dev_tools_enabled = !command_line.HasSwitch(
@@ -419,6 +426,7 @@ void RenderView::OnMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_HANDLER(ViewMsg_SetBackground, OnSetBackground)
     IPC_MESSAGE_HANDLER(ViewMsg_EnableIntrinsicWidthChangedMode,
                         OnEnableIntrinsicWidthChangedMode)
+    IPC_MESSAGE_HANDLER(ViewMsg_SetRendererPrefs, OnSetRendererPrefs)
 
     // Have the super handle all other messages.
     IPC_MESSAGE_UNHANDLED(RenderWidget::OnMessageReceived(message))
@@ -1003,6 +1011,10 @@ void RenderView::UpdateSessionHistory(WebFrame* frame) {
 ///////////////////////////////////////////////////////////////////////////////
 // WebViewDelegate
 
+bool RenderView::CanAcceptLoadDrops() const {
+  return renderer_preferences_.can_accept_load_drops;
+}
+
 void RenderView::DidStartLoading(WebView* webview) {
   if (is_loading_) {
     DLOG(WARNING) << "DidStartLoading called while loading";
@@ -1657,7 +1669,7 @@ WebView* RenderView::CreateWebView(WebView* webview,
   }
 
   // The WebView holds a reference to this new RenderView
-  const WebPreferences& prefs = webview->GetPreferences();
+  const WebPreferences& web_prefs = webview->GetPreferences();
   base::WaitableEvent* waitable_event = new base::WaitableEvent
 #if defined(OS_WIN)
       (modal_dialog_event.event);
@@ -1666,8 +1678,8 @@ WebView* RenderView::CreateWebView(WebView* webview,
 #endif
   RenderView* view = RenderView::Create(render_thread_,
                                         NULL, waitable_event, routing_id_,
-                                        prefs, shared_popup_counter_,
-                                        routing_id);
+                                        renderer_preferences_, web_prefs,
+                                        shared_popup_counter_, routing_id);
   view->opened_by_user_gesture_ = user_gesture;
   view->creator_url_ = creator_url;
 
@@ -2518,6 +2530,10 @@ void RenderView::OnEnableIntrinsicWidthChangedMode() {
   send_preferred_width_changes_ = true;
 }
 
+void RenderView::OnSetRendererPrefs(const RendererPreferences& renderer_prefs) {
+  renderer_preferences_ = renderer_prefs;
+}
+
 void RenderView::OnUpdateBackForwardListCount(int back_list_count,
                                               int forward_list_count) {
   history_back_list_count_ = back_list_count;
diff --git a/chrome/renderer/render_view.h b/chrome/renderer/render_view.h
index a0dd47a..f661b02 100644
--- a/chrome/renderer/render_view.h
+++ b/chrome/renderer/render_view.h
@@ -18,6 +18,7 @@
 #include "base/timer.h"
 #include "base/values.h"
 #include "build/build_config.h"
+#include "chrome/browser/renderer_preferences.h"
 #include "chrome/renderer/automation/dom_automation_controller.h"
 #include "chrome/renderer/dom_ui_bindings.h"
 #include "chrome/renderer/extensions/extension_process_bindings.h"
@@ -113,6 +114,7 @@ class RenderView : public RenderWidget,
       gfx::NativeViewId parent_hwnd,
       base::WaitableEvent* modal_dialog_event,  // takes ownership
       int32 opener_id,
+      const RendererPreferences& renderer_prefs,
       const WebPreferences& webkit_prefs,
       SharedRenderViewCounter* counter,
       int32 routing_id);
@@ -137,6 +139,7 @@ class RenderView : public RenderWidget,
   virtual void OnMessageReceived(const IPC::Message& msg);
 
   // WebViewDelegate
+  virtual bool CanAcceptLoadDrops() const;
   virtual void ShowModalHTMLDialog(const GURL& url, int width, int height,
                                    const std::string& json_arguments,
                                    std::string* json_retval);
@@ -410,6 +413,7 @@ class RenderView : public RenderWidget,
   void Init(gfx::NativeViewId parent,
             base::WaitableEvent* modal_dialog_event,  // takes ownership
             int32 opener_id,
+            const RendererPreferences& renderer_prefs,
             const WebPreferences& webkit_prefs,
             SharedRenderViewCounter* counter,
             int32 routing_id);
@@ -540,6 +544,7 @@ class RenderView : public RenderWidget,
   void OnFileChooserResponse(const std::vector<FilePath>& file_names);
   void OnEnableViewSourceMode();
   void OnEnableIntrinsicWidthChangedMode();
+  void OnSetRendererPrefs(const RendererPreferences& renderer_prefs);
   void OnUpdateBackForwardListCount(int back_list_count,
                                     int forward_list_count);
   void OnGetAccessibilityInfo(
@@ -799,6 +804,8 @@ class RenderView : public RenderWidget,
   // Need for printing
   scoped_ptr<PrintWebViewHelper> print_render_view_;
 
+  RendererPreferences renderer_preferences_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderView);
 };
 
diff --git a/chrome/test/render_view_test.cc b/chrome/test/render_view_test.cc
index 20665f1..0ff6793 100644
--- a/chrome/test/render_view_test.cc
+++ b/chrome/test/render_view_test.cc
@@ -6,6 +6,7 @@
 
 #include "chrome/common/native_web_keyboard_event.h"
 #include "chrome/common/render_messages.h"
+#include "chrome/browser/renderer_preferences.h"
 #include "chrome/browser/extensions/extension_function_dispatcher.h"
 #include "chrome/renderer/extensions/event_bindings.h"
 #include "chrome/renderer/extensions/extension_process_bindings.h"
@@ -85,7 +86,7 @@ void RenderViewTest::SetUp() {
 
   // This needs to pass the mock render thread to the view.
   view_ = RenderView::Create(&render_thread_, NULL, NULL, kOpenerId,
-                             WebPreferences(),
+                             RendererPreferences(), WebPreferences(),
                              new SharedRenderViewCounter(0), kRouteId);
 
   // Attach a pseudo keyboard device to this object.
diff --git a/webkit/glue/dragclient_impl.cc b/webkit/glue/dragclient_impl.cc
index 6199fed..1a7d73d 100644
--- a/webkit/glue/dragclient_impl.cc
+++ b/webkit/glue/dragclient_impl.cc
@@ -44,7 +44,13 @@ void DragClientImpl::willPerformDragSourceAction(
 
 WebCore::DragDestinationAction DragClientImpl::actionMaskForDrag(
     WebCore::DragData*) {
-  return WebCore::DragDestinationActionAny;
+  if (webview_->delegate()->CanAcceptLoadDrops()) {
+    return WebCore::DragDestinationActionAny;
+  } else {
+    return static_cast<WebCore::DragDestinationAction>
+        (WebCore::DragDestinationActionDHTML |
+         WebCore::DragDestinationActionEdit);
+  }
 }
 
 WebCore::DragSourceAction DragClientImpl::dragSourceActionMaskForPoint(
diff --git a/webkit/glue/webview_delegate.h b/webkit/glue/webview_delegate.h
index a4b5061..7609eff 100644
--- a/webkit/glue/webview_delegate.h
+++ b/webkit/glue/webview_delegate.h
@@ -181,6 +181,12 @@ class WebViewDelegate : virtual public WebWidgetDelegate {
 
   // FrameLoaderClient -------------------------------------------------------
 
+  virtual bool CanAcceptLoadDrops() const {
+    // Always return true here so layout tests (which use the default WebView
+    // delegate) continue to pass.
+    return true;
+  }
+
   // Notifies the delegate that a load has begun.
   virtual void DidStartLoading(WebView* webview) {
   }