Remaining changes to build all code in src.git with -Wimplicit-fallthrough.

This CL was uploaded by git cl split.

R=bauerb@chromium.org

Bug: 177475
Change-Id: I83ec9e5eab7e96de49808c6ce1506aef1ea9bd55
Reviewed-on: https://chromium-review.googlesource.com/891902Reviewed-by: Bernhard Bauer <bauerb@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532845}

chrome/browser/prefs/tracked/pref_hash_browsertest.cc

@@ -688,18 +688,16 @@ class PrefHashBrowserTestUntrustedInitialized : public PrefHashBrowserTestBase {
     // the previous one.
     switch (protection_level_) {
       case PROTECTION_ENABLED_ALL:
-        // Falls through.
       case PROTECTION_ENABLED_EXTENSIONS:
         ++num_protected_prefs;
-        // Falls through.
+        FALLTHROUGH;
       case PROTECTION_ENABLED_DSE:
         ++num_protected_prefs;
-        // Falls through.
+        FALLTHROUGH;
       case PROTECTION_ENABLED_BASIC:
         num_protected_prefs += num_tracked_prefs() - num_null_values - 2;
-        // Falls through.
+        FALLTHROUGH;
       case PROTECTION_DISABLED_FOR_GROUP:
-        // No protection. Falls through.
       case PROTECTION_DISABLED_ON_PLATFORM:
         // No protection.
         break;