GCC on the buildbots is more picky

base/waitable_event_posix.cc

 // Copyright (c) 2006-2008 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 "base/waitable_event.h"
 
 #include "base/condition_variable.h"
 #include "base/lock.h"
 #include "base/message_loop.h"
 
@@ skipping 253 matching lines @@
       if (sw.fired())
         break;
 
       cv.Wait();
     }
   lock.Release();
 
   // The address of the WaitableEvent which fired is stored in the SyncWaiter.
   WaitableEvent *const signaled_event = sw.signaled_event();
   // This will store the index of the raw_waitables which fired.
-  size_t signaled_index;
+  size_t signaled_index = 0;
 
   // Take the locks of each WaitableEvent in turn (except the signaled one) and
   // remove our SyncWaiter from the wait-list
   for (size_t i = 0; i < count; ++i) {
     if (raw_waitables[i] != signaled_event) {
       raw_waitables[i]->lock_.Acquire();
         // There's no possible ABA issue with the address of the SyncWaiter here
         // because it lives on the stack. Thus the tag value is just the pointer
         // value again.
         raw_waitables[i]->Dequeue(&sw, &sw);
@@ skipping 98 matching lines @@
       return true;
     }
   }
 
   return false;
 }
 
 // -----------------------------------------------------------------------------
 
 }  // namespace base