cocoa: give bookmarks menu an accessible title

Without this VoiceOver reads the window title, which is "BmbPopUpWindow".

BUG=641496

Review-Url: https://codereview.chromium.org/2320723006
Cr-Commit-Position: refs/heads/master@{#417573}

chrome/app/generated_resources.grd

@@ -7434,6 +7434,10 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_ACCNAME_BOOKMARKS_CHEVRON" desc="The accessible name for the chevron visible if not all the bookmark buttons fit.">
         Menu containing hidden bookmarks
       </message>
+      <message name="IDS_ACCNAME_BOOKMARKS_MENU" desc="The accessible name for
+the Bookmarks menu.">
+        Bookmarks menu
+      </message>
       <message name="IDS_ACCNAME_SEPARATOR" desc="The accessible name for a separator.">
         Separator
       </message>

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

@@ -8,7 +8,9 @@
 #import "base/mac/scoped_nsobject.h"
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_constants.h"
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_folder_controller.h"
+#include "chrome/grit/generated_resources.h"
 #import "third_party/google_toolbox_for_mac/src/AppKit/GTMNSColor+Luminance.h"
+#include "ui/base/l10n/l10n_util_mac.h"
 #include "ui/base/material_design/material_design_controller.h"
 
 using bookmarks::kBookmarkBarMenuCornerRadius;
@@ -20,6 +22,12 @@ const CGFloat kMDFolderWindowBackgroundColor = 237. / 255.;
 
 }  // namespace
 
+@interface BookmarkBarFolderWindow (Accessibility)
+
+- (NSString*)accessibilityTitle;
+
+@end
+
 @implementation BookmarkBarFolderWindow
 
 - (id)initWithContentRect:(NSRect)contentRect
@@ -48,6 +56,12 @@ const CGFloat kMDFolderWindowBackgroundColor = 237. / 255.;
 - (void)keyDown:(NSEvent *)theEvent {
 }
 
+// If the menu doesn't have a separate accessibleTitle, it will get announced as
+// its normal window title, which is "BmbPopUpWindow".
+- (NSString*)accessibilityTitle {
+  return l10n_util::GetNSString(IDS_ACCNAME_BOOKMARKS_MENU);
+}
+
 @end