Made FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE #ifdef out less

This is to protect against cases where part of a project is
compiled with or without this flag, making for very fragile
and hard to find bugs, such as sizeof(Verifier) changing.

Change-Id: I01c895cdc5b44f860e4b0b9c9613bff1983e2b9d
See: https://bugs.chromium.org/p/chromium/issues/detail?id=929847

include/flatbuffers/flatbuffers.h

@@ -1977,13 +1977,9 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
         depth_(0),
         max_depth_(_max_depth),
         num_tables_(0),
-        max_tables_(_max_tables)
-  // clang-format off
-    #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
-        , upper_bound_(0)
-    #endif
-        , check_alignment_(_check_alignment)
-  // clang-format on
+        max_tables_(_max_tables),
+        upper_bound_(0),
+        check_alignment_(_check_alignment)
   {
     FLATBUFFERS_ASSERT(size_ < FLATBUFFERS_MAX_BUFFER_SIZE);
   }
@@ -2174,17 +2170,21 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
     return true;
   }
 
-  // clang-format off
-  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
   // Returns the message size in bytes
   size_t GetComputedSize() const {
+    // clang-format off
+    #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
       uintptr_t size = upper_bound_;
       // Align the size to uoffset_t
       size = (size - 1 + sizeof(uoffset_t)) & ~(sizeof(uoffset_t) - 1);
       return (size > size_) ?  0 : size;
-  }
+    #else
+      // Must turn on FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE for this to work.
+      FLATBUFFERS_ASSERT(false);
+      return 0;
     #endif
     // clang-format on
+  }
 
  private:
   const uint8_t *buf_;
@@ -2193,11 +2193,7 @@ class Verifier FLATBUFFERS_FINAL_CLASS {
   uoffset_t max_depth_;
   uoffset_t num_tables_;
   uoffset_t max_tables_;
-  // clang-format off
-  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
   mutable size_t upper_bound_;
-  #endif
-  // clang-format on
   bool check_alignment_;
 };
 

tests/test.cpp

@@ -210,6 +210,8 @@ void AccessFlatBufferTest(const uint8_t *flatbuf, size_t length,
   flatbuffers::Verifier verifier(flatbuf, length);
   TEST_EQ(VerifyMonsterBuffer(verifier), true);
 
+  // clang-format off
+  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
     std::vector<uint8_t> test_buff;
     test_buff.resize(length * 2);
     std::memcpy(&test_buff[0], flatbuf, length);
@@ -222,6 +224,8 @@ void AccessFlatBufferTest(const uint8_t *flatbuf, size_t length,
     flatbuffers::Verifier verifier2(&test_buff[length], length);
     TEST_EQ(VerifyMonsterBuffer(verifier2), true);
     TEST_EQ(verifier2.GetComputedSize(), length);
+  #endif
+  // clang-format on
 
   TEST_EQ(strcmp(MonsterIdentifier(), "MONS"), 0);
   TEST_EQ(MonsterBufferHasIdentifier(flatbuf), true);