Put classes under dictionary/file to mozc::dictionary namespace.

This is just a code cleanup.  Hence no behavior change should occur.

BUG=none
TEST=unittest
diff --git a/src/converter/converter_test.cc b/src/converter/converter_test.cc
index d3178cf..b9feb80 100644
--- a/src/converter/converter_test.cc
+++ b/src/converter/converter_test.cc
@@ -81,6 +81,7 @@
 DECLARE_string(test_tmpdir);
 
 using mozc::dictionary::DictionaryImpl;
+using mozc::dictionary::DictionaryMock;
 using mozc::dictionary::SuffixDictionary;
 using mozc::dictionary::SuffixToken;
 using mozc::dictionary::SuppressionDictionary;
diff --git a/src/dictionary/dictionary_mock.cc b/src/dictionary/dictionary_mock.cc
index 020eb7a..e007a09 100644
--- a/src/dictionary/dictionary_mock.cc
+++ b/src/dictionary/dictionary_mock.cc
@@ -41,6 +41,7 @@
 #include "dictionary/dictionary_token.h"
 
 namespace mozc {
+namespace dictionary {
 namespace {
 
 const int kDummyPosId = 1;
@@ -258,4 +259,5 @@
       CreateToken(str, key, value, attributes));
 }
 
+}  // namespace dictionary
 }  // namespace mozc
diff --git a/src/dictionary/dictionary_mock.h b/src/dictionary/dictionary_mock.h
index 5899eae..ecd1bb6 100644
--- a/src/dictionary/dictionary_mock.h
+++ b/src/dictionary/dictionary_mock.h
@@ -62,6 +62,7 @@
 #include "dictionary/dictionary_token.h"
 
 namespace mozc {
+namespace dictionary {
 
 class DictionaryMock : public DictionaryInterface {
  public:
@@ -127,6 +128,8 @@
 
   DISALLOW_COPY_AND_ASSIGN(DictionaryMock);
 };
+
+}  // namespace dictionary
 }  // namespace mozc
 
 #endif  // MOZC_DICTIONARY_DICTIONARY_MOCK_H_
diff --git a/src/dictionary/dictionary_mock_test.cc b/src/dictionary/dictionary_mock_test.cc
index ba254fa..a2216a6 100644
--- a/src/dictionary/dictionary_mock_test.cc
+++ b/src/dictionary/dictionary_mock_test.cc
@@ -40,9 +40,9 @@
 #include "testing/base/public/googletest.h"
 #include "testing/base/public/gunit.h"
 
-using mozc::dictionary::CollectTokenCallback;
-
 namespace mozc {
+namespace dictionary {
+namespace {
 
 class DictionaryMockTest : public ::testing::Test {
  protected:
@@ -236,4 +236,6 @@
   EXPECT_TRUE(callback.tokens().empty());
 }
 
+}  // namespace
+}  // namespace dictionary
 }  // namespace mozc
diff --git a/src/dictionary/file/codec.cc b/src/dictionary/file/codec.cc
index 0e6418f..5e20359 100644
--- a/src/dictionary/file/codec.cc
+++ b/src/dictionary/file/codec.cc
@@ -42,6 +42,7 @@
 
 
 namespace mozc {
+namespace dictionary {
 namespace {
 
 void WriteInt(int value, ostream *ofs) {
@@ -142,13 +143,13 @@
 }
 
 namespace {
-DictionaryFileCodecInterface *g_dictionary_file_codec = NULL;
+DictionaryFileCodecInterface *g_dictionary_file_codec = nullptr;
 }  // namespace
 
 typedef DictionaryFileCodec DefaultCodec;
 
 DictionaryFileCodecInterface *DictionaryFileCodecFactory::GetCodec() {
-  if (g_dictionary_file_codec == NULL) {
+  if (g_dictionary_file_codec == nullptr) {
     return Singleton<DefaultCodec>::get();
   } else {
     return g_dictionary_file_codec;
@@ -159,4 +160,5 @@
   g_dictionary_file_codec = codec;
 }
 
+}  // namespace dictionary
 }  // namespace mozc
diff --git a/src/dictionary/file/codec.h b/src/dictionary/file/codec.h
index 5f5ea27..e54dee6 100644
--- a/src/dictionary/file/codec.h
+++ b/src/dictionary/file/codec.h
@@ -41,6 +41,7 @@
 #include "dictionary/file/section.h"
 
 namespace mozc {
+namespace dictionary {
 
 
 class DictionaryFileCodec : public DictionaryFileCodecInterface {
@@ -66,6 +67,7 @@
   DISALLOW_COPY_AND_ASSIGN(DictionaryFileCodec);
 };
 
+}  // namespace dictionary
 }  // namespace mozc
 
 #endif  // MOZC_DICTIONARY_FILE_CODEC_H_
diff --git a/src/dictionary/file/codec_interface.h b/src/dictionary/file/codec_interface.h
index 5ce5f51..d4a09ca 100644
--- a/src/dictionary/file/codec_interface.h
+++ b/src/dictionary/file/codec_interface.h
@@ -37,18 +37,19 @@
 #include "dictionary/file/section.h"
 
 namespace mozc {
+namespace dictionary {
 
 class DictionaryFileCodecInterface {
  public:
-  // Write sections to output file stream
+  // Writes sections to an output file stream.
   virtual void WriteSections(const vector<DictionaryFileSection> &sections,
                              ostream *ofs) const = 0;
 
-  // Read sections from memory image
+  // Reads sections from memory image.
   virtual bool ReadSections(const char *image, int length,
                             vector<DictionaryFileSection> *sections) const = 0;
 
-  // Get section name
+  // Gets section name.
   virtual string GetSectionName(const string &name) const = 0;
 
  protected:
@@ -61,16 +62,17 @@
 
 class DictionaryFileCodecFactory {
  public:
-  // return singleton object
+  // Returns the singleton instance.
   static DictionaryFileCodecInterface *GetCodec();
 
-  // dependency injectin for unittesting
+  // For dependency injectin in unit tests.
   static void SetCodec(DictionaryFileCodecInterface *codec);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(DictionaryFileCodecFactory);
 };
 
+}  // namespace dictionary
 }  // namespace mozc
 
 #endif  // MOZC_DICTIONARY_FILE_CODEC_INTERFACE_H_
diff --git a/src/dictionary/file/codec_test.cc b/src/dictionary/file/codec_test.cc
index 59b0445..996af6a 100644
--- a/src/dictionary/file/codec_test.cc
+++ b/src/dictionary/file/codec_test.cc
@@ -42,6 +42,7 @@
 DECLARE_string(test_tmpdir);
 
 namespace mozc {
+namespace dictionary {
 namespace {
 
 class CodecTest : public ::testing::Test {
@@ -222,4 +223,5 @@
 
 
 }  // namespace
+}  // namespace dictionary
 }  // namespace mozc
diff --git a/src/dictionary/file/dictionary_file.cc b/src/dictionary/file/dictionary_file.cc
index 50a7ab8..2501d66 100644
--- a/src/dictionary/file/dictionary_file.cc
+++ b/src/dictionary/file/dictionary_file.cc
@@ -38,6 +38,7 @@
 #include "dictionary/file/section.h"
 
 namespace mozc {
+namespace dictionary {
 
 DictionaryFile::DictionaryFile() {}
 
@@ -68,6 +69,8 @@
       return sections_[i].ptr;
     }
   }
-  return NULL;
+  return nullptr;
 }
+
+}  // namespace dictionary
 }  // namespace mozc
diff --git a/src/dictionary/file/dictionary_file.h b/src/dictionary/file/dictionary_file.h
index 63ddac1..4e5c7e7 100644
--- a/src/dictionary/file/dictionary_file.h
+++ b/src/dictionary/file/dictionary_file.h
@@ -36,11 +36,13 @@
 #include <string>
 #include <vector>
 
+#include "base/mmap.h"
 #include "base/port.h"
 #include "base/scoped_ptr.h"
 
 namespace mozc {
-class Mmap;
+namespace dictionary {
+
 struct DictionaryFileSection;
 
 class DictionaryFile {
@@ -60,13 +62,14 @@
   const char *GetSection(const string &section_name, int *len) const;
 
  private:
-  // This will be NULL if the mapping source is given as a pointer.
+  // This will be nullptr if the mapping source is given as a pointer.
   scoped_ptr<Mmap> mapping_;
-
   vector<DictionaryFileSection> sections_;
 
   DISALLOW_COPY_AND_ASSIGN(DictionaryFile);
 };
-}
+
+}  // namespace dictionary
+}  // namespace mozc
 
 #endif  // MOZC_DICTIONARY_FILE_DICTIONARY_FILE_H_
diff --git a/src/dictionary/file/dictionary_file_builder.cc b/src/dictionary/file/dictionary_file_builder.cc
index 2777465..a8f2681 100644
--- a/src/dictionary/file/dictionary_file_builder.cc
+++ b/src/dictionary/file/dictionary_file_builder.cc
@@ -38,6 +38,7 @@
 #include "dictionary/file/section.h"
 
 namespace mozc {
+namespace dictionary {
 
 DictionaryFileBuilder::DictionaryFileBuilder() {}
 
@@ -62,16 +63,15 @@
   ifs.seekg(0, ios::end);
   const int len = ifs.tellg();
 
-  // reads the file
+  // Reads the file
   ifs.seekg(0, ios::beg);
   char *ptr = new char[len];
   ifs.read(ptr, len);
 
   sections_.push_back(DictionaryFileSection(ptr, len, ""));
 
-  const string name =
+  sections_.back().name =
       DictionaryFileCodecFactory::GetCodec()->GetSectionName(section_name);
-  sections_.back().name = name;
 
   return true;
 }
@@ -82,4 +82,6 @@
   DictionaryFileCodecFactory::GetCodec()->WriteSections(sections_, &ofs);
   LOG(INFO) << "Generated";
 }
+
+}  // namespace dictionary
 }  // namespace mozc
diff --git a/src/dictionary/file/dictionary_file_builder.h b/src/dictionary/file/dictionary_file_builder.h
index 3b33ad8..508b406 100644
--- a/src/dictionary/file/dictionary_file_builder.h
+++ b/src/dictionary/file/dictionary_file_builder.h
@@ -38,17 +38,17 @@
 #include "dictionary/file/section.h"
 
 namespace mozc {
+namespace dictionary {
+
 class DictionaryFileBuilder {
  public:
   DictionaryFileBuilder();
-
   virtual ~DictionaryFileBuilder();
 
-  // Add section from file
-  bool AddSectionFromFile(const string &section_name,
-                          const string &file_name);
+  // Adds a section from a file
+  bool AddSectionFromFile(const string &section_name, const string &file_name);
 
-  // Write image of dictionary file to file
+  // Writes the image of dictionary file to a file.
   void WriteImageToFile(const string &file_name) const;
 
  private:
@@ -57,6 +57,8 @@
 
   DISALLOW_COPY_AND_ASSIGN(DictionaryFileBuilder);
 };
+
+}  // namespace dictionary
 }  // namespace mozc
 
 #endif  // MOZC_DICTIONARY_FILE_DICTIONARY_FILE_BUILDER_H_
diff --git a/src/dictionary/file/dictionary_file_test.cc b/src/dictionary/file/dictionary_file_test.cc
index 09f6c74..2ff7730 100644
--- a/src/dictionary/file/dictionary_file_test.cc
+++ b/src/dictionary/file/dictionary_file_test.cc
@@ -30,6 +30,7 @@
 #include "dictionary/file/dictionary_file.h"
 
 #include <cstdio>
+#include <string>
 
 #include "base/file_util.h"
 #include "base/flags.h"
@@ -41,6 +42,7 @@
 DECLARE_string(test_tmpdir);
 
 namespace mozc {
+namespace dictionary {
 namespace {
 
 TEST(DictionaryFileTest, Basic) {
@@ -89,4 +91,5 @@
 }
 
 }  // namespace
+}  // namespace dictionary
 }  // namespace mozc
diff --git a/src/dictionary/file/section.h b/src/dictionary/file/section.h
index d472bc3..bc562aa 100644
--- a/src/dictionary/file/section.h
+++ b/src/dictionary/file/section.h
@@ -30,18 +30,22 @@
 #ifndef MOZC_DICTIONARY_FILE_SECTION_H_
 #define MOZC_DICTIONARY_FILE_SECTION_H_
 
+#include <cstddef>
 #include <string>
 
 namespace mozc {
+namespace dictionary {
+
 struct DictionaryFileSection {
+  DictionaryFileSection(const char *ptr, size_t len, const string &name)
+      : ptr(ptr), len(len), name(name) {}
+
   const char *ptr;
   size_t len;
   string name;
-
-  DictionaryFileSection(const char *ptr, size_t len, const string &name)
-      : ptr(ptr), len(len), name(name) {
-  }
 };
+
+}  // namespace dictionary
 }  // namespace mozc
 
 #endif  // MOZC_DICTIONARY_FILE_SECTION_H_
diff --git a/src/dictionary/system/system_dictionary.h b/src/dictionary/system/system_dictionary.h
index 29bf908..5de8d51 100644
--- a/src/dictionary/system/system_dictionary.h
+++ b/src/dictionary/system/system_dictionary.h
@@ -45,11 +45,9 @@
 #include "storage/louds/louds_trie.h"
 
 namespace mozc {
-
-class DictionaryFile;
-
 namespace dictionary {
 
+class DictionaryFile;
 class SystemDictionaryCodecInterface;
 
 class SystemDictionary : public DictionaryInterface {
diff --git a/src/dictionary/system/value_dictionary.h b/src/dictionary/system/value_dictionary.h
index 1783351..d05fffc 100644
--- a/src/dictionary/system/value_dictionary.h
+++ b/src/dictionary/system/value_dictionary.h
@@ -42,22 +42,19 @@
 #include "dictionary/dictionary_interface.h"
 
 namespace mozc {
-
-namespace dictionary {
-class SystemDictionaryCodecInterface;
-}  // namespace dictionary
-
 namespace storage {
 namespace louds {
 class LoudsTrie;
 }  // namespace louds
 }  // namespace storage
 
-class DictionaryFile;
 class POSMatcher;
 
 namespace dictionary {
 
+class DictionaryFile;
+class SystemDictionaryCodecInterface;
+
 class ValueDictionary : public DictionaryInterface {
  public:
   virtual ~ValueDictionary();
diff --git a/src/mozc_version_template.txt b/src/mozc_version_template.txt
index e3e2748..dbd0dad 100644
--- a/src/mozc_version_template.txt
+++ b/src/mozc_version_template.txt
@@ -1,6 +1,6 @@
 MAJOR=2
 MINOR=17
-BUILD=2086
+BUILD=2087
 REVISION=102
 # NACL_DICTIONARY_VERSION is the target version of the system dictionary to be
 # downloaded by NaCl Mozc.
diff --git a/src/prediction/dictionary_predictor_test.cc b/src/prediction/dictionary_predictor_test.cc
index fbc3e0c..c8c9e8a 100644
--- a/src/prediction/dictionary_predictor_test.cc
+++ b/src/prediction/dictionary_predictor_test.cc
@@ -74,6 +74,7 @@
 #include "transliteration/transliteration.h"
 
 using ::testing::_;
+using mozc::dictionary::DictionaryMock;
 using mozc::dictionary::SuffixDictionary;
 using mozc::dictionary::SuffixToken;
 using mozc::dictionary::SuppressionDictionary;
diff --git a/src/prediction/predictor_test.cc b/src/prediction/predictor_test.cc
index 4276b3b..9f8ee6c 100644
--- a/src/prediction/predictor_test.cc
+++ b/src/prediction/predictor_test.cc
@@ -56,6 +56,7 @@
 using ::testing::AtMost;
 using ::testing::Return;
 using ::testing::_;
+using mozc::dictionary::DictionaryMock;
 using mozc::dictionary::SuppressionDictionary;
 
 namespace mozc {
diff --git a/src/prediction/user_history_predictor_test.cc b/src/prediction/user_history_predictor_test.cc
index b955cd3..a9f8312 100644
--- a/src/prediction/user_history_predictor_test.cc
+++ b/src/prediction/user_history_predictor_test.cc
@@ -57,6 +57,7 @@
 DECLARE_bool(enable_expansion_for_user_history_predictor);
 
 using mozc::commands::Request;
+using mozc::dictionary::DictionaryMock;
 using mozc::dictionary::SuppressionDictionary;
 
 namespace mozc {
diff --git a/src/rewriter/language_aware_rewriter_test.cc b/src/rewriter/language_aware_rewriter_test.cc
index c0892b5..7ecb0fa 100644
--- a/src/rewriter/language_aware_rewriter_test.cc
+++ b/src/rewriter/language_aware_rewriter_test.cc
@@ -55,9 +55,11 @@
 
 DECLARE_string(test_tmpdir);
 
-namespace mozc {
+using mozc::dictionary::DictionaryMock;
 
+namespace mozc {
 namespace {
+
 void InsertASCIISequence(const string &text, composer::Composer *composer) {
   for (size_t i = 0; i < text.size(); ++i) {
     commands::KeyEvent key;
@@ -65,6 +67,7 @@
     composer->InsertCharacterKeyEvent(key);
   }
 }
+
 }  // namespace
 
 class LanguageAwareRewriterTest : public testing::Test {