[Mac] Fix build break with r52223.

chrome/browser/cocoa/location_bar/autocomplete_text_field_cell.mm

 // Copyright (c) 2010 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 "chrome/browser/cocoa/location_bar/autocomplete_text_field_cell.h"
 
 #include "base/logging.h"
 #import "chrome/browser/cocoa/image_utils.h"
 #import "chrome/browser/cocoa/location_bar/location_bar_decoration.h"
 
@@ skipping 631 matching lines @@
       (decoration && decoration->IsDraggable())) {
     DCHECK(icon || decoration);
     NSDate* timeout =
         [NSDate dateWithTimeIntervalSinceNow:kLocationIconDragTimeout];
     NSEvent* event = [NSApp nextEventMatchingMask:(NSLeftMouseDraggedMask |
                                                    NSLeftMouseUpMask)
                                         untilDate:timeout
                                            inMode:NSEventTrackingRunLoopMode
                                           dequeue:YES];
     if (!event || [event type] == NSLeftMouseDragged) {
-      NSPasteboard* pboard;
+      NSPasteboard* pboard = nil;
       if (icon) pboard = [icon view]->GetDragPasteboard();
       if (decoration) pboard = decoration->GetDragPasteboard();
       DCHECK(pboard);
 
       // TODO(shess): My understanding is that the -isFlipped
       // adjustment should not be necessary.  But without it, the
       // image is nowhere near the cursor.  Perhaps the icon's rect is
       // incorrectly calculated?
       // http://crbug.com/40711
       NSPoint dragPoint = decorationRect.origin;
       if ([controlView isFlipped])
         dragPoint.y += NSHeight(decorationRect);
 
-      NSImage* image;
+      NSImage* image = nil;
       if (icon) image = [icon view]->GetImage();
       if (decoration) image = decoration->GetDragImage();
       [controlView dragImage:image
                           at:dragPoint
                       offset:NSZeroSize
                        event:event ? event : theEvent
                   pasteboard:pboard
                       source:self
                    slideBack:YES];
       return YES;
@@ skipping 11 matching lines @@
   }
 
   return YES;
 }
 
 - (NSDragOperation)draggingSourceOperationMaskForLocal:(BOOL)isLocal {
   return NSDragOperationCopy;
 }
 
 @end