Inherit default text color from MainTheme.

chrome/android/java/res/layout/account_chooser_dialog_title.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2015 The Chromium Authors. All rights reserved.
      Use of this source code is governed by a BSD-style license that can be
      found in the LICENSE file. -->
 
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:padding="@dimen/account_chooser_dialog_margin"
     android:orientation="vertical">
     <TextView
         android:id="@+id/title"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:ellipsize="end"
         android:lineSpacingExtra="4dp"
         android:fontFamily="sans-serif"
-        android:textSize="@dimen/account_chooser_dialog_title_main_text_size"
-        android:textColor="@color/default_text_color"/>
+        android:textSize="@dimen/account_chooser_dialog_title_main_text_size" />
     <TextView
         android:id="@+id/origin"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:ellipsize="end"
         android:paddingTop="8dp"
         android:fontFamily="sans-serif"
         android:textSize="@dimen/account_chooser_dialog_title_descriptive_text_size"
         android:textColor="@color/descriptive_text_color"/>
-
 </LinearLayout>