[Mac] Don't crash when selecting closed window from Dock menu.

chrome/browser/chrome_application_mac.mm

Index: chrome/browser/chrome_application_mac.mm
diff --git a/chrome/browser/chrome_application_mac.mm b/chrome/browser/chrome_application_mac.mm
index 8c7d86014781eb42b8e6523f939fb92ebd349c69..a94d3aac93e1ead66cf62586da73bee921eae574 100644
--- a/chrome/browser/chrome_application_mac.mm
+++ b/chrome/browser/chrome_application_mac.mm
@@ -58,4 +58,29 @@
   // own.
 }
 
+- (BOOL)sendAction:(SEL)anAction to:(id)aTarget from:(id)sender {
+  // The Dock menu contains an automagic section where you can select
+  // amongst open windows.  If a window is closed via JavaScript while
+  // the menu is up, the menu item for that window continues to exist.
+  // When a window is selected this method is called with the
+  // now-freed window as |aTarget|.  Short-circuit the call if
+  // |aTarget| is not a valid window.
+  if (anAction == @selector(_selectWindow:)) {
+    // Not using -[NSArray containsObject:] because |aTarget| may be a
+    // freed object.
+    BOOL found = NO;
+    for (NSWindow* window in [self windows]) {
+      if (window == aTarget) {
+        found = YES;
+        break;
+      }
+    }
+    if (!found) {
+      return NO;
+    }
+  }
+
+  return [super sendAction:anAction to:aTarget from:sender];
+}
+
 @end