[spelling] existance to existence

tools/gn/variables.cc

 // Copyright (c) 2013 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 "tools/gn/variables.h"
 
 namespace variables {
 
 // Built-in variables ----------------------------------------------------------
 
@@ skipping 1697 matching lines @@
     R"(sources: Source files for a target
 
   A list of files. Non-absolute paths will be resolved relative to the current
   build file.
 
 Sources for binary targets
 
   For binary targets (source sets, executables, and libraries), the known file
   types will be compiled with the associated tools. Unknown file types and
   headers will be skipped. However, you should still list all C/C+ header files
-  so GN knows about the existance of those files for the purposes of include
+  so GN knows about the existence of those files for the purposes of include
   checking.
 
   As a special case, a file ending in ".def" will be treated as a Windows
   module definition file. It will be appended to the link line with a
   preceeding "/DEF:" string. There must be at most one .def file in a target
   and they do not cross dependency boundaries (so specifying a .def file in a
   static library or source set will have no effect on the executable or shared
   library they're linked into).
 
 Sources for non-binary targets
@@ skipping 205 matching lines @@
     INSERT_VARIABLE(Testonly)
     INSERT_VARIABLE(Visibility)
     INSERT_VARIABLE(WriteRuntimeDeps)
   }
   return info_map;
 }
 
 #undef INSERT_VARIABLE
 
 }  // namespace variables