Update WebAPK if homescreen icon changed.

chrome/android/webapk/shell_apk/AndroidManifest.xml

Index: chrome/android/webapk/shell_apk/AndroidManifest.xml
diff --git a/chrome/android/webapk/shell_apk/AndroidManifest.xml b/chrome/android/webapk/shell_apk/AndroidManifest.xml
index 90a9958be316a45f93a849edbf054c17b391532a..fae86daf1f63294aef0539b0fcead22d836df05c 100644
--- a/chrome/android/webapk/shell_apk/AndroidManifest.xml
+++ b/chrome/android/webapk/shell_apk/AndroidManifest.xml
@@ -45,6 +45,7 @@
         <meta-data android:name="org.chromium.webapk.shell_apk.themeColor" android:value="{{ theme_color }}" />
         <meta-data android:name="org.chromium.webapk.shell_apk.backgroundColor" android:value="{{ background_color }}" />
         <meta-data android:name="org.chromium.webapk.shell_apk.iconUrl" android:value="{{ icon_url }}" />
+        <meta-data android:name="org.chromium.webapk.shell_apk.iconMurmur2Hash" android:value="{{ icon_murmur2_hash }} " />
         <meta-data android:name="org.chromium.webapk.shell_apk.webManifestUrl" android:value="{{ web_manifest_url }}" />
         <service
             android:name="org.chromium.webapk.shell_apk.WebApkServiceFactory"