Add message_composer.xml

app/src/main/res/layout/message_composer.xml

+<?xml version="1.0" encoding="utf-8"?>
+<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content">
+
+    <View
+        android:id="@+id/divider"
+        android:layout_width="match_parent"
+        android:layout_height="1dp"
+        android:background="@color/colorDividerMessageComposer" />
+
+    <LinearLayout
+        android:id="@+id/top_container"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginEnd="@dimen/screen_edge_left_and_right_margins"
+        android:layout_marginStart="@dimen/screen_edge_left_and_right_margins"
+        android:layout_marginTop="10dp"
+        android:orientation="horizontal"
+        android:paddingBottom="10dp"
+        app:layout_constraintTop_toBottomOf="@+id/divider">
+
+        <EditText
+            android:id="@+id/text_message"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginEnd="8dp"
+            android:layout_weight="1"
+            android:background="@android:color/transparent"
+            android:hint="@string/msg_message"
+            android:maxLines="4" />
+
+        <TextView
+            android:id="@+id/text_send"
+            style="@style/TextAppearance.AppCompat.Medium"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:background="?android:attr/selectableItemBackgroundBorderless"
+            android:clickable="true"
+            android:focusable="true"
+            android:text="@string/action_send"
+            android:textColor="@color/colorAccent" />
+    </LinearLayout>
+
+</android.support.constraint.ConstraintLayout>
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