Minor fixes to tools/gn.

tools/gn/substitution_type.h

 // Copyright 2014 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.
 
 #ifndef TOOLS_GN_SUBSTITUTION_TYPE_H_
 #define TOOLS_GN_SUBSTITUTION_TYPE_H_
 
 #include <vector>
 
 class Err;
 class ParseNode;
 
 // Keep kSubstitutionNames, kSubstitutionNinjaNames and the
-// IsValid*Substutition functions in sync if you change anything here.
+// IsValid*Substitution functions in sync if you change anything here.
 enum SubstitutionType {
   SUBSTITUTION_LITERAL = 0,
 
   // The index of the first pattern. To loop overal all patterns, go from here
   // until NUM_TYPES.
   SUBSTITUTION_FIRST_PATTERN,
 
   // These map to Ninja's {in} and {out} variables.
   SUBSTITUTION_SOURCE = SUBSTITUTION_FIRST_PATTERN,  // {{source}}
   SUBSTITUTION_OUTPUT,  // {{output}}
@@ skipping 61 matching lines @@
 
   // Converts the substitution type bitfield (with a true set for each required
   // item) to a vector of the types listed. Does not include LITERAL.
   void FillVector(std::vector<SubstitutionType>* vect) const;
 
   bool used[SUBSTITUTION_NUM_TYPES];
 };
 
 // Returns true if the given substitution pattern references the output
 // directory. This is used to check strings that begin with a substitution to
-// verify that the produce a file in the output directory.
+// verify that they produce a file in the output directory.
 bool SubstitutionIsInOutputDir(SubstitutionType type);
 
 // Returns true if the given substitution is valid for the named purpose.
 bool IsValidSourceSubstitution(SubstitutionType type);
 // Both compiler and linker tools.
-bool IsValidToolSubstutition(SubstitutionType type);
+bool IsValidToolSubstitution(SubstitutionType type);
 bool IsValidCompilerSubstitution(SubstitutionType type);
 bool IsValidCompilerOutputsSubstitution(SubstitutionType type);
 bool IsValidLinkerSubstitution(SubstitutionType type);
 bool IsValidLinkerOutputsSubstitution(SubstitutionType type);
 bool IsValidCopySubstitution(SubstitutionType type);
 
 // Like the "IsValid..." version above but checks a list of types and sets a
 // an error blaming the given source if the test fails.
 bool EnsureValidSourcesSubstitutions(
     const std::vector<SubstitutionType>& types,
     const ParseNode* origin,
     Err* err);
 
 #endif  // TOOLS_GN_SUBSTITUTION_TYPE_H_