Don't send a DragLeave to the renderer if we didn't send a DragEnter.

content/browser/web_contents/web_drag_dest_mac.mm

 // Copyright (c) 2012 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.
 
 #import "content/browser/web_contents/web_drag_dest_mac.h"
 
 #import <Carbon/Carbon.h>
 
 #include "base/sys_string_conversions.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
@@ skipping 124 matching lines @@
   // hear back from the renderer. For now, be optimistic:
   currentOperation_ = NSDragOperationCopy;
   return currentOperation_;
 }
 
 - (void)draggingExited:(id<NSDraggingInfo>)info {
   DCHECK(currentRVH_);
   if (currentRVH_ != webContents_->GetRenderViewHost())
     return;
 
-  // Nothing to do in the interstitial case.
+  if ([self onlyAllowsNavigation]) {

[sky, 2012/07/18 20:58:43]

no {}

+    return;
+  }
 
   if (delegate_)
     delegate_->OnDragLeave();
 
   webContents_->GetRenderViewHost()->DragTargetDragLeave();
   dropData_.reset();
 }
 
 - (NSDragOperation)draggingUpdated:(id<NSDraggingInfo>)info
                               view:(NSView*)view {
@@ skipping 24 matching lines @@
 
   return currentOperation_;
 }
 
 - (BOOL)performDragOperation:(id<NSDraggingInfo>)info
                               view:(NSView*)view {
   if (currentRVH_ != webContents_->GetRenderViewHost())
     [self draggingEntered:info view:view];
 
   // Check if we only allow navigation and navigate to a url on the pasteboard.
-  BOOL result = YES;
   if ([self onlyAllowsNavigation]) {
     NSPasteboard* pboard = [info draggingPasteboard];
     if ([pboard containsURLData]) {
       GURL url;
       ui::PopulateURLAndTitleFromPasteboard(&url, NULL, pboard, YES);
       webContents_->OpenURL(OpenURLParams(
           url, Referrer(), CURRENT_TAB, content::PAGE_TRANSITION_AUTO_BOOKMARK,
           false));
+      return YES;
     } else {
-      result = NO;
+      return NO;
     }
-  } else {
-    if (delegate_)
-      delegate_->OnDrop();
   }
 
+  if (delegate_)
+    delegate_->OnDrop();
+
   currentRVH_ = NULL;
 
   // Create the appropriate mouse locations for WebCore. The draggingLocation
   // is in window coordinates. Both need to be flipped.
   NSPoint windowPoint = [info draggingLocation];
   NSPoint viewPoint = [self flipWindowPointToView:windowPoint view:view];
   NSPoint screenPoint = [self flipWindowPointToScreen:windowPoint view:view];
   webContents_->GetRenderViewHost()->DragTargetDrop(
       gfx::Point(viewPoint.x, viewPoint.y),
       gfx::Point(screenPoint.x, screenPoint.y),
       GetModifierFlags());
 
   dropData_.reset();
 
-  return result;
+  return YES;
 }
 
 // Given |data|, which should not be nil, fill it in using the contents of the
 // given pasteboard. The types handled by this method should be kept in sync
 // with [WebContentsViewCocoa registerDragTypes].
 - (void)populateWebDropData:(WebDropData*)data
              fromPasteboard:(NSPasteboard*)pboard {
   DCHECK(data);
   DCHECK(pboard);
   NSArray* types = [pboard types];
@@ skipping 44 matching lines @@
   // Get custom MIME data.
   if ([types containsObject:ui::kWebCustomDataPboardType]) {
     NSData* customData = [pboard dataForType:ui::kWebCustomDataPboardType];
     ui::ReadCustomDataIntoMap([customData bytes],
                               [customData length],
                               &data->custom_data);
   }
 }
 
 @end