Fix 64 bit truncation errors in mojo WTF traits.

Cast or use appropriate type where applicable.

BUG=879657

Change-Id: I94f2a425e14281978bce8bfaf256f69b90af7bda
Reviewed-on: https://chromium-review.googlesource.com/c/1347047Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610874}

mojo/public/cpp/bindings/array_traits_wtf_vector.h

@@ -37,16 +37,18 @@ struct ArrayTraits<WTF::Vector<U, InlineCapacity>> {
   }
 
   static U& GetAt(WTF::Vector<U, InlineCapacity>& input, size_t index) {
-    return input[index];
+    return input[static_cast<wtf_size_t>(index)];
   }
 
   static const U& GetAt(const WTF::Vector<U, InlineCapacity>& input,
                         size_t index) {
-    return input[index];
+    return input[static_cast<wtf_size_t>(index)];
   }
 
   static bool Resize(WTF::Vector<U, InlineCapacity>& input, size_t size) {
-    input.resize(size);
+    if (!base::IsValueInRangeForNumericType<wtf_size_t>(size))
+      return false;
+    input.resize(static_cast<wtf_size_t>(size));
     return true;
   }
 };

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

@@ -43,7 +43,7 @@ struct EqualsTraits<WTF::Vector<T>, false> {
   static bool Equals(const WTF::Vector<T>& a, const WTF::Vector<T>& b) {
     if (a.size() != b.size())
       return false;
-    for (size_t i = 0; i < a.size(); ++i) {
+    for (wtf_size_t i = 0; i < a.size(); ++i) {
       if (!mojo::Equals(a[i], b[i]))
         return false;
     }

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

@@ -60,7 +60,7 @@ size_t WTFHash(size_t seed, const T& value) {
 template <typename T>
 struct StructPtrHashFn {
   static unsigned GetHash(const StructPtr<T>& value) {
-    return value.Hash(kHashSeed);
+    return static_cast<unsigned>(value.Hash(kHashSeed));
   }
   static bool Equal(const StructPtr<T>& left, const StructPtr<T>& right) {
     return left.Equals(right);
@@ -71,7 +71,7 @@ struct StructPtrHashFn {
 template <typename T>
 struct InlinedStructPtrHashFn {
   static unsigned GetHash(const InlinedStructPtr<T>& value) {
-    return value.Hash(kHashSeed);
+    return static_cast<unsigned>(value.Hash(kHashSeed));
   }
   static bool Equal(const InlinedStructPtr<T>& left,
                     const InlinedStructPtr<T>& right) {