Inherit default text color from MainTheme.

chrome/android/java/res/values-v17/styles.xml

Index: chrome/android/java/res/values-v17/styles.xml
diff --git a/chrome/android/java/res/values-v17/styles.xml b/chrome/android/java/res/values-v17/styles.xml
index 0fe3eb93c79853d9eae94a6a79ae21b503353449..457269b3a3c73a9d881163441d1a6b1540f17328 100644
--- a/chrome/android/java/res/values-v17/styles.xml
+++ b/chrome/android/java/res/values-v17/styles.xml
@@ -23,6 +23,7 @@
         <item name="android:textColorHighlight">@color/text_highlight_color</item>
         <item name="android:textColorLink">@color/light_active_color</item>
         <item name="android:statusBarColor" tools:targetApi="21">@android:color/black</item>
+        <item name="android:textColor">@color/default_text_color</item>
 
         <!--  Overriding AppCompat values -->
         <item name="colorControlNormal">@color/light_normal_color</item>
@@ -47,6 +48,7 @@
 
     <style name="FullscreenWhiteDialog" parent="Theme.AppCompat.Light" >
         <item name="android:windowBackground">@android:color/white</item>
+        <item name="android:textColor">@color/default_text_color</item>
         <item name="android:textColorLink">@color/light_active_color</item>
         <item name="android:statusBarColor" tools:targetApi="21">@android:color/black</item>
         <item name="colorPrimary">@color/light_active_color</item>