[apps/sequence] SequenceTitleCell reload

SequenceTitleCell::reloadCell now triggers a layoutSubviews, causing the
vertical alignment to be recomputed. This solves issues regarding the
alignment of a sequence's name and definition, such as :
  - typing u_n = v_n ; v_n would be displayed above u_n
  - typing u_n = (1/3)/2 then changing to u_n = 1/(2/3) without erasing
    the formula first. u_n would no longer be aligned with the = sign.

Change-Id: I4a771d96ea79e42e2f4822e93f9f1cbbcf867610

apps/sequence/sequence_title_cell.cpp

@@ -43,6 +43,16 @@ void SequenceTitleCell::setColor(KDColor color) {
   m_titleTextView.setTextColor(color);
 }
 
+void SequenceTitleCell::reloadCell() {
+  /* When creating a new sequence, the layout has not yet been initialized, but
+   * it is needed in layoutSubview to compute the vertical alignment. */
+  if (TreeNode::IsValidIdentifier(layout().identifier())) {
+    layoutSubviews();
+  }
+  m_titleTextView.reloadCell();
+  FunctionTitleCell::reloadCell();
+}
+
 int SequenceTitleCell::numberOfSubviews() const {
   return 1;
 }
@@ -53,6 +63,7 @@ View * SequenceTitleCell::subviewAtIndex(int index) {
 }
 
 void SequenceTitleCell::layoutSubviews(bool force) {
+  assert(TreeNode::IsValidIdentifier(layout().identifier()));
   if (m_orientation == Orientation::VerticalIndicator) {
     m_titleTextView.setAlignment(k_verticalOrientationHorizontalAlignment, verticalAlignment());
   }

apps/sequence/sequence_title_cell.h

@@ -20,6 +20,7 @@ public:
   Poincare::Layout layout() const override {
     return m_titleTextView.layout();
   }
+  void reloadCell() override;
 private:
   static constexpr float k_horizontalOrientationAlignment = 0.5f;
   static constexpr float k_verticalOrientationHorizontalAlignment = 0.9f;