Explicitly set windowLightStatusBar in theme

Explicitly set windowLightStatusBar to false in Theme.Chromium along
with setting the status bar color to black. This is already the default
value, but setting it explicitly allows this theme (and its many
descendents) to be safely applied to a window where that status bar was
previously light with dark icons. Otherwise, as in crbug.com/1002846,
the status bar will appear "blank".

Bug: 1002846
Change-Id: I875333e5708308d02a92257dd6b8d87906ccc85b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1804679Reviewed-by: Theresa  <twellington@chromium.org>
Commit-Queue: Natalie Chouinard <chouinard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696872}

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

@@ -17,6 +17,7 @@
 
         <!-- Status bar color -->
         <item name="android:statusBarColor" tools:targetApi="21">@android:color/black</item>
+        <item name="android:windowLightStatusBar" tools:targetApi="23">false</item>
         <item name="colorPrimaryDark">@android:color/black</item>
 
         <!-- Text colors -->