Remove unneeded extern keywords in components/.

Change-Id: Ia5f0d37480f95d9412f3d4f4534e227c9dae3733
Reviewed-on: https://chromium-review.googlesource.com/c/1357765Reviewed-by: Cait Phillips <caitkp@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613307}

components/autofill/core/browser/suggestion_selection.cc

@@ -51,11 +51,11 @@ base::string16 GetInfoInOneLine(const AutofillProfile* profile,
 
 // As of November 2018, 50 profiles should be more than enough to cover at least
 // 99% of all times the dropdown is shown.
-extern const size_t kMaxSuggestedProfilesCount = 50;
+constexpr size_t kMaxSuggestedProfilesCount = 50;
 
 // As of November 2018, displaying 10 suggestions cover at least 99% of the
 // indices clicked by our users. The suggestions will also refine as they type.
-extern const size_t kMaxUniqueSuggestionsCount = 10;
+constexpr size_t kMaxUniqueSuggestionsCount = 10;
 
 std::vector<Suggestion> GetPrefixMatchedSuggestions(
     const AutofillType& type,

components/autofill/core/common/autofill_features.cc

@@ -290,7 +290,7 @@ const base::Feature kAutofillUpstreamUseGooglePayBrandingOnMobile{
     base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Controls whether to use the API or use the legacy server.
-extern const base::Feature kAutofillUseApi{"AutofillUseApi",
+const base::Feature kAutofillUseApi{"AutofillUseApi",
                                     base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Controls whether the PaymentsCustomerData is used to make requests to

components/autofill/core/common/autofill_switches.cc

@@ -19,7 +19,7 @@ const char kAutofillServerURL[] = "autofill-server-url";
 // The randomized encoding type to use when sending metadata uploads. The
 // value of the parameter must be one of the valid integer values of the
 // AutofillRandomizedValue_EncodingType enum.
-extern const char kAutofillMetadataUploadEncoding[] =
+const char kAutofillMetadataUploadEncoding[] =
     "autofill-metadata-upload-encoding";
 
 // Force hiding the local save checkbox in the autofill dialog box for getting

components/component_updater/component_updater_url_constants.cc

@@ -20,10 +20,10 @@ const char kUpdaterDefaultUrl[] =
 const char kUpdaterFallbackUrl[] =
     "http://update.googleapis.com/service/update2";
 
-extern const char kUpdaterJSONDefaultUrl[] =
+const char kUpdaterJSONDefaultUrl[] =
     "https://update.googleapis.com/service/update2/json";
 
-extern const char kUpdaterJSONFallbackUrl[] =
+const char kUpdaterJSONFallbackUrl[] =
     "http://update.googleapis.com/service/update2/json";
 
 }  // namespace component_updater

components/sync/syncable/directory_backing_store_unittest.cc

@@ -47,9 +47,6 @@ std::unique_ptr<EntryKernel> CreateEntry(int id, const std::string& id_suffix) {
 
 }  // namespace
 
-extern const int32_t kCurrentPageSizeKB;
-extern const int32_t kCurrentDBVersion;
-
 class MigrationTest : public testing::TestWithParam<int> {
  public:
   void SetUp() override { ASSERT_TRUE(temp_dir_.CreateUniqueTempDir()); }