More clear comment for ValidateStructHeader.

BUG=None
TEST=None
R=viettrungluu@chromium.org

Review URL: https://codereview.chromium.org/328183002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@276546 0039d316-1c4b-4281-b951-d872f2087c98

mojo/public/cpp/bindings/lib/bindings_serialization.cc

@@ -84,6 +84,8 @@ bool ValidateStructHeader(const void* data,
                           uint32_t min_num_bytes,
                           uint32_t min_num_fields,
                           BoundsChecker* bounds_checker) {
+  assert(min_num_bytes >= sizeof(StructHeader));
+
   if (!IsAligned(data)) {
     ReportValidationError(VALIDATION_ERROR_MISALIGNED_OBJECT);
     return false;

mojo/public/cpp/bindings/lib/bindings_serialization.h

@@ -71,6 +71,7 @@ inline void Decode(T* obj, std::vector<Handle>* handles) {
 
 // If returns true, this function also claims the memory range of the size
 // specified in the struct header, starting from |data|.
+// Note: |min_num_bytes| must be no less than sizeof(StructHeader).
 bool ValidateStructHeader(const void* data,
                           uint32_t min_num_bytes,
                           uint32_t min_num_fields,