Suppress implicit-fallthrough warnings.

Add FALLTHROUGH_INTENDED for clang compiler.

Bug: 112564944
Test: build with global -Wimplicit-fallthrough.
Change-Id: I40f8bbf94e207c9dd90921e9b762ba51abab5777
diff --git a/libutils/Unicode.cpp b/libutils/Unicode.cpp
index 82f650d..5f0a51f 100644
--- a/libutils/Unicode.cpp
+++ b/libutils/Unicode.cpp
@@ -16,8 +16,9 @@
 
 #define LOG_TAG "unicode"
 
-#include <utils/Unicode.h>
+#include <android-base/macros.h>
 #include <limits.h>
+#include <utils/Unicode.h>
 
 #include <log/log.h>
 
@@ -105,8 +106,11 @@
     switch (bytes)
     {   /* note: everything falls through. */
         case 4: *--dstP = (uint8_t)((srcChar | kByteMark) & kByteMask); srcChar >>= 6;
+            FALLTHROUGH_INTENDED;
         case 3: *--dstP = (uint8_t)((srcChar | kByteMark) & kByteMask); srcChar >>= 6;
+            FALLTHROUGH_INTENDED;
         case 2: *--dstP = (uint8_t)((srcChar | kByteMark) & kByteMask); srcChar >>= 6;
+            FALLTHROUGH_INTENDED;
         case 1: *--dstP = (uint8_t)(srcChar | kFirstByteMark[bytes]);
     }
 }