Clean up bookmark_bar_folder_view testing. Specifically get it working with OCMock.

chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_view.mm

Index: chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_view.mm
diff --git a/chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_view.mm b/chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_view.mm
index eff63dba30519699d2da80924d7b180ff8f576cb..a434b1b62162bdca36fa1c593ad690f185a3129d 100644
--- a/chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_view.mm
+++ b/chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_view.mm
@@ -15,6 +15,7 @@
 
 @synthesize dropIndicatorShown = dropIndicatorShown_;
 @synthesize dropIndicatorPosition = dropIndicatorPosition_;
+@synthesize controller = controller_;
 
 - (void)awakeFromNib {
   NSArray* types = [NSArray arrayWithObjects:
@@ -32,16 +33,12 @@
   [super dealloc];
 }
 
-- (id<BookmarkButtonControllerProtocol>)controller {
+- (BookmarkBarFolderController*)controller {
   // When needed for testing, set the local data member |controller_| to
   // the test controller.
   return controller_ ? controller_ : [[self window] windowController];
 }
 
-- (void)setController:(id)controller {
-  controller_ = controller;
-}
-
 - (void)drawRect:(NSRect)rect {
   // TODO(jrg): copied from bookmark_bar_view but orientation changed.
   // Code dup sucks but I'm not sure I can take 16 lines and make it