[Mac] Log OnChannelError() bt for CHECK in bug 97285.

content/renderer/plugin_channel_host.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/plugin_channel_host.h"
 
 #include "base/metrics/histogram.h"
 #include "base/time.h"
 #include "content/common/child_process.h"
 #include "content/common/npobject_base.h"
@@ skipping 18 matching lines @@
 #if defined(OS_MACOSX)
 #include "base/debug/stack_trace.h"
 #include "base/mac/crash_logging.h"
 #include "base/sys_string_conversions.h"
 
 namespace {
 
 // Breakpad key for the RemoveRoute() backtrace.
 const char* kRemoveRouteTraceKey = "remove_route_bt";
 
+// Breakpad key for the OnChannelError() backtrace.
+const char* kChannelErrorTraceKey = "channel_error_bt";
+
 // GetRemoveTrackingFlag() exposes this so that
 // WebPluginDelegateProxy::Initialize() can do scoped set/reset.  When
 // true, RemoveRoute() knows WBDP::Initialize() is on the stack, and
 // records the backtrace.
 bool remove_tracking = false;
 
 }  // namespace
 #endif
 
 // A simple MessageFilter that will ignore all messages and respond to sync
@@ skipping 146 matching lines @@
     base::TimeTicks start_time(base::TimeTicks::Now());
     bool result = NPChannelBase::Send(msg);
     UMA_HISTOGRAM_TIMES("Plugin.SyncMessageTime",
                         base::TimeTicks::Now() - start_time);
     return result;
   }
   return NPChannelBase::Send(msg);
 }
 
 void PluginChannelHost::OnChannelError() {
+#if defined(OS_MACOSX)
+  if (remove_tracking) {
+    base::debug::StackTrace trace;
+    size_t count = 0;
+    const void* const* addresses = trace.Addresses(&count);
+    base::mac::SetCrashKeyFromAddresses(
+        base::SysUTF8ToNSString(kChannelErrorTraceKey), addresses, count);
+  }
+#endif
+
   NPChannelBase::OnChannelError();
 
   for (ProxyMap::iterator iter = proxies_.begin();
        iter != proxies_.end(); iter++) {
     iter->second->OnChannelError();
   }
 
   proxies_.clear();
 }