Disallow copy and assign of EmbeddedVector

EmbeddedVector lives on the stack only, and should not be implicitly
copied or assigned.
This also removes remaining uses of the removed Vector::set_start
method.

R=sigurds@chromium.org

Bug: v8:9142
Change-Id: I829e6ffad6b1a30baa6c874265e92d615dd0c981
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1578458Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60940}

src/vector.h

@@ -315,28 +315,14 @@ class EmbeddedVector : public Vector<T> {
  public:
   EmbeddedVector() : Vector<T>(buffer_, kSize) {}
 
-  explicit EmbeddedVector(T initial_value) : Vector<T>(buffer_, kSize) {
-    for (int i = 0; i < kSize; ++i) {
-      buffer_[i] = initial_value;
-    }
-  }
-
-  // When copying, make underlying Vector to reference our buffer.
-  EmbeddedVector(const EmbeddedVector& rhs) V8_NOEXCEPT : Vector<T>(rhs) {
-    MemCopy(buffer_, rhs.buffer_, sizeof(T) * kSize);
-    this->set_start(buffer_);
-  }
-
-  EmbeddedVector& operator=(const EmbeddedVector& rhs) V8_NOEXCEPT {
-    if (this == &rhs) return *this;
-    Vector<T>::operator=(rhs);
-    MemCopy(buffer_, rhs.buffer_, sizeof(T) * kSize);
-    this->set_start(buffer_);
-    return *this;
+  explicit EmbeddedVector(const T& initial_value) : Vector<T>(buffer_, kSize) {
+    std::fill_n(buffer_, kSize, initial_value);
   }
 
  private:
   T buffer_[kSize];
+
+  DISALLOW_COPY_AND_ASSIGN(EmbeddedVector);
 };
 
 }  // namespace internal