Simplify libcrash_dumper interface and make window_manager gen crash dumps

src/platform/crash/crash_dumper.h

 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CRASH_CRASH_DUMPER_H_
 #define CRASH_CRASH_DUMPER_H_
 
-#include <string>
-
-#include "base/scoped_ptr.h"
-
-namespace google_breakpad {
-class ExceptionHandler;
-}
-
-class FilePath;
-
 // Class to manage crash handling and dumping.  When Enable is called, all
 // crashes will be caught and stored to the appropriate crash directory.
 // The directory will be:
 //   /home/chronos/user/crash - for all processes running as chronos
 //   /var/spool/crash - for all other processes
 // The class takes care of creating the directories (even recreating them
 // at crash time in case the cryptohome mounting changes from Enable time.
+//
+// For most use cases, there is no need to include or call any functions
+// explicitly in this header file.  Crash dumping is enabled just by linking
+// in libcrash_dumper.
 
 class CrashDumper {
  public:
+  CrashDumper() {
+    Enable();
+  }
+
   ~CrashDumper() {
     if (IsEnabled()) {
       Disable();
     }
   }
 
   // Enable crash detection and dumping.  Aborts if already enabled
   // or crash reporting cannot be enabled.  If the cryptohome is mounted
   // while crash handling is enabled, later crashes may be lost.
   static void Enable();
 
   // Return if enabled.
   static bool IsEnabled();
 
   // Disable crash detection and dumping.  Aborts if not enabled.
   static void Disable();
 };
 
 #endif  // CRASH_CRASH_DUMPER_H_