Work more on getting things built with -Wimplicit-fallthrough.

This CL was uploaded by git cl split.

R=nhiroki@chromium.org

Bug: 177475
Change-Id: Ia487f9629a4b9c129d6361a6720fd9782819ef80
Reviewed-on: https://chromium-review.googlesource.com/890064Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532359}

storage/browser/fileapi/sandbox_directory_database.cc

@@ -764,7 +764,7 @@ bool SandboxDirectoryDatabase::Init(RecoveryOption recovery_option) {
       UMA_HISTOGRAM_ENUMERATION(kDatabaseRepairHistogramLabel,
                                 DB_REPAIR_FAILED, DB_REPAIR_MAX);
       LOG(WARNING) << "Failed to repair SandboxDirectoryDatabase.";
-      // fall through
+      FALLTHROUGH;
     case DELETE_ON_CORRUPTION:
       LOG(WARNING) << "Clearing SandboxDirectoryDatabase.";
       if (!base::DeleteFile(filesystem_data_directory_, true))

storage/browser/fileapi/sandbox_origin_database.cc

@@ -112,7 +112,7 @@ bool SandboxOriginDatabase::Init(InitOption init_option,
       }
       UMA_HISTOGRAM_ENUMERATION(kDatabaseRepairHistogramLabel,
                                 DB_REPAIR_FAILED, DB_REPAIR_MAX);
-      // fall through
+      FALLTHROUGH;
     case DELETE_ON_CORRUPTION:
       if (!base::DeleteFile(file_system_directory_, true))
         return false;