[Mac] Add breakpad info for crashes in the target/action dispatcher.

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 a81326f73710d817c39bbc20e15021f4a63cdf96..2457dc27961c478173acc9348b4ddaf3eb207401 100644
--- a/chrome/browser/chrome_application_mac.mm
+++ b/chrome/browser/chrome_application_mac.mm
@@ -4,6 +4,30 @@
 
 #import "chrome/browser/chrome_application_mac.h"
 
+#import "base/scoped_nsobject.h"
+#import "chrome/app/breakpad_mac.h"
+
+namespace {
+
+// Helper to make it easy to get crash keys right.
+// TODO(shess): Find a better home for this.  app/breakpad_mac.h
+// doesn't work.
+class ScopedCrashKey {
+ public:
+  ScopedCrashKey(NSString* key, NSString* value)
+      : crash_key_([key retain]) {
+    SetCrashKeyValue(crash_key_.get(), value);
+  }
+  ~ScopedCrashKey() {
+    ClearCrashKeyValue(crash_key_.get());
+  }
+
+ private:
+  scoped_nsobject<NSString> crash_key_;
+};
+
+}  // namespace
+
 @implementation CrApplication
 
 // -terminate: is the entry point for orderly "quit" operations in Cocoa.
@@ -80,6 +104,29 @@
     }
   }
 
+  // When a Cocoa control is wired to a freed object, we get crashers
+  // in the call to |super| with no useful information in the
+  // backtrace.  Attempt to add some useful information.
+  static const NSString* kActionKey = @"sendaction";
+
+  // If the action is something generic like -commandDispatch:, then
+  // the tag is essential.
+  NSInteger tag = 0;
+  if ([sender isKindOfClass:[NSControl class]]) {
+    tag = [sender tag];
+    if (tag == 0 || tag == -1) {
+      tag = [sender selectedTag];
+    }
+  } else if ([sender isKindOfClass:[NSMenuItem class]]) {
+    tag = [sender tag];
+  }
+
+  NSString* actionString = NSStringFromSelector(anAction);
+  NSString* value =
+        [NSString stringWithFormat:@"%@ tag %d sending %@ to %p",
+                  [sender className], tag, actionString, aTarget];
+
+  ScopedCrashKey key(kActionKey, value);
   return [super sendAction:anAction to:aTarget from:sender];
 }