[Mac] Log stack trace for CHECK in bug 97285.

The hypothesis in comment #55 on the bug is that while setting up a
new channel to an already-connected plugin,
NPChannelBase::RemoveRoute() can be called on the earlier channel, so
the renderer and plugin channel mappings get out of sync.  This will
add a Breakpad key encoding the top stack frames when RemoveRoute() is
called within the scoped of WebPluginDelegateProxy::Initialize().

objc_zombies.mm already implemented the stackframe-encoding code, so I
pulled that to a central location.  That code can be left in place
when the other code is removed after some traces are generated.

BUG=97285
TEST=crash server.


Review URL: https://chromiumcodereview.appspot.com/10408004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@137896 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 4 insertions, 14 deletions

diff --git a/chrome/common/mac/objc_zombie.mm b/chrome/common/mac/objc_zombie.mm
index e5d3a82..5ef00a6 100644
--- a/chrome/common/mac/objc_zombie.mm
+++ b/chrome/common/mac/objc_zombie.mm
@@ -290,21 +290,11 @@ void ZombieObjectCrash(id object, SEL aSelector, SEL viaSelector) {
   // Set a value for breakpad to report.
   base::mac::SetCrashKeyValue(@"zombie", aString);
 
-  // Hex-encode the backtrace and tuck it into a breakpad key.
-  NSString* deallocTrace = @"<unknown>";
-  if (found && record.traceDepth) {
-    NSMutableArray* hexBacktrace =
-        [NSMutableArray arrayWithCapacity:record.traceDepth];
-    for (size_t i = 0; i < record.traceDepth; ++i) {
-      NSString* s = [NSString stringWithFormat:@"%p", record.trace[i]];
-      [hexBacktrace addObject:s];
-    }
-    deallocTrace = [hexBacktrace componentsJoinedByString:@" "];
-
-    // Warn someone if this exceeds the breakpad limits.
-    DCHECK_LE(strlen([deallocTrace UTF8String]), 255U);
+  // Encode trace into a breakpad key.
+  if (found) {
+    base::mac::SetCrashKeyFromAddresses(
+        @"zombie_dealloc_bt", record.trace, record.traceDepth);
   }
-  base::mac::SetCrashKeyValue(@"zombie_dealloc_bt", deallocTrace);
 
   // Log -dealloc backtrace in debug builds then crash with a useful
   // stack trace.