Truncate the Javascript alert message if the length is too long on Mac port

chrome/browser/ui/cocoa/javascript_app_modal_dialog_cocoa.mm

Index: chrome/browser/ui/cocoa/javascript_app_modal_dialog_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/javascript_app_modal_dialog_cocoa.mm b/chrome/browser/ui/cocoa/javascript_app_modal_dialog_cocoa.mm
index 7341835b372e3527306b29bcf4a07474317b3d93..7eef1ac3d5a505d86064ba565254000dea27a031 100644
--- a/chrome/browser/ui/cocoa/javascript_app_modal_dialog_cocoa.mm
+++ b/chrome/browser/ui/cocoa/javascript_app_modal_dialog_cocoa.mm
@@ -17,6 +17,8 @@
 #include "ui/base/l10n/l10n_util_mac.h"
 #include "ui/base/ui_base_types.h"
 
+const int kMessageTextMaxRows = 32;
+
 // Helper object that receives the notification that the dialog/sheet is
 // going away. Is responsible for cleaning itself up.
 @interface JavaScriptAppModalDialogHelper : NSObject<NSAlertDelegate> {
@@ -146,6 +148,19 @@ JavaScriptAppModalDialogCocoa::JavaScriptAppModalDialogCocoa(
   [alert_ setDelegate:helper_];
   NSString* informative_text =
       base::SysUTF16ToNSString(dialog_->message_text());
+
+  // Truncate long JS alerts - crbug.com/331219
+  NSArray * info_array =
+      [informative_text componentsSeparatedByCharactersInSet:
+          [NSCharacterSet newlineCharacterSet]];
+  if ([info_array count] > kMessageTextMaxRows) {
+    NSRange info_range = NSMakeRange(0, kMessageTextMaxRows);
+    info_array = [info_array subarrayWithRange:info_range];
+    info_array = [info_array valueForKey:@"description"];

[jeremy, 2014/01/22 20:16:03]

What is this meant to do?

+    informative_text = [info_array componentsJoinedByString:@"\n"];
+    informative_text = [informative_text stringByAppendingString:@"\n..."];
+  }
+
   [alert_ setInformativeText:informative_text];
   NSString* message_text =
       base::SysUTF16ToNSString(dialog_->title());