weblayer: updates shell manifest to adjust view for keyboard

This is what chrome/content do to ensure the keyboard doesn't occlude any web
content.

BUG=1029720
TEST=test only change

Change-Id: Ib12f5b5fbd5a9cca6415451413ab400c7f03aeb9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1948323Reviewed-by: Clark DuVall <cduvall@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721087}

weblayer/shell/android/shell_apk/AndroidManifest.xml

@@ -13,7 +13,7 @@
         <activity android:name="WebLayerShellActivity"
                   android:launchMode="singleTask"
                   android:theme="@android:style/Theme.Holo.Light.NoActionBar"
-                  android:windowSoftInputMode="adjustPan|stateUnspecified"
+                  android:windowSoftInputMode="adjustResize"
                   android:configChanges="orientation|screenSize">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>