Mac: Fix a crash on "Look Up in Dictionary" context menu.

chrome/browser/tab_contents/render_view_context_menu_mac.mm

Index: chrome/browser/tab_contents/render_view_context_menu_mac.mm
diff --git a/chrome/browser/tab_contents/render_view_context_menu_mac.mm b/chrome/browser/tab_contents/render_view_context_menu_mac.mm
index 582f8addedf652528b0b828769a98caec45ff92d..1e4e4c4089c11c8f5377142ee568fc01459d82f4 100644
--- a/chrome/browser/tab_contents/render_view_context_menu_mac.mm
+++ b/chrome/browser/tab_contents/render_view_context_menu_mac.mm
@@ -77,6 +77,10 @@ void RenderViewContextMenuMac::LookUpInDictionary() {
   // don't support it: http://crbug.com/17951
   NSString* text = base::SysWideToNSString(params_.selection_text);
   NSPasteboard* pboard = [NSPasteboard pasteboardWithUniqueName];
+  // 10.5 and earlier require declareTypes before setData.
+  // See the documentation on [NSPasteboard declareTypes].
+  NSArray* toDeclare = [NSArray arrayWithObject:NSStringPboardType];
+  [pboard declareTypes:toDeclare owner:nil];
   BOOL ok = [pboard setString:text forType:NSStringPboardType];
   if (ok)
     NSPerformService(@"Look Up in Dictionary", pboard);