[CollapsingToolbarLayout] Exposing methods to set text size for collapsed and expanded text size

Resolves #775

PiperOrigin-RevId: 465391478

Author: imhappi

lib/java/com/google/android/material/appbar/CollapsingToolbarLayout.java

@@ -1185,6 +1185,34 @@ public int getExpandedTitleGravity() {
     return collapsingTextHelper.getExpandedTextGravity();
   }
 
+  /**
+   * Sets the text size of the expanded title.
+   *
+   * @param textSize The text size of the expanded title.
+   */
+  public void setExpandedTitleTextSize(float textSize) {
+    collapsingTextHelper.setExpandedTextSize(textSize);
+  }
+
+  /** Returns the text size of the expanded title. */
+  public float getExpandedTitleTextSize() {
+    return collapsingTextHelper.getExpandedTextSize();
+  }
+
+  /**
+   * Sets the text size of the collapsed title.
+   *
+   * @param textSize The text size of the collapsed title.
+   */
+  public void setCollapsedTitleTextSize(float textSize) {
+    collapsingTextHelper.setCollapsedTextSize(textSize);
+  }
+
+  /** Returns the text size of the collapsed title. */
+  public float getCollapsedTitleTextSize() {
+    return collapsingTextHelper.getCollapsedTextSize();
+  }
+
   /**
    * Set the typeface to use for the collapsed title.
    *