Update WebAPK if homescreen icon changed.

chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java b/chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java
index 936279dd595f5887c23ef20d07d17be46255304f..9bf5f3791ba8094ba8befc34e73b89758d2fde83 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java
@@ -38,6 +38,7 @@ import org.chromium.chrome.browser.webapps.WebappDataStorage;
 import org.chromium.chrome.browser.webapps.WebappLauncherActivity;
 import org.chromium.chrome.browser.webapps.WebappRegistry;
 import org.chromium.chrome.browser.widget.RoundedIconGenerator;
+import org.chromium.content_public.browser.WebContents;
 import org.chromium.content_public.common.ScreenOrientationConstants;
 import org.chromium.ui.widget.Toast;
 import org.chromium.webapk.lib.client.WebApkValidator;
@@ -99,6 +100,14 @@ public class ShortcutHelper {
     private static final float GENERATED_ICON_PADDING_RATIO = 1.0f / 12.0f;
     private static final float GENERATED_ICON_FONT_SIZE_RATIO = 1.0f / 3.0f;
 
+    /**
+     * Callback to {@link fetchHomescreenImage()}. Called once the homescreen image has been
+     * fetched.
+     */
+    public interface FetchHomescreenImageCallback {
+        public void onFetchedHomescreenImage(Bitmap bitmap, long murmur2Hash);
+    }
+
     /** Broadcasts Intents out Android for adding the shortcut. */
     public static class Delegate {
         /**
@@ -419,6 +428,24 @@ public class ShortcutHelper {
     }
 
     /**
+     * Fetches the image at {@link iconUrl} and scales it so that it can be used on the homescreen.

[dominickn, 2016/08/15 05:27:34]

This comment is confusing - does nativeFetchHomescreenImage do any scaling? Is
the icon actually used on the homescreen? It doesn't seem to pass through
ShortcutHelper#createHomescreenIconFromWebIcon, where all A2HS icons are sent
for optional padding before being dropped in the launcher.

+     */
+    public static void fetchHomescreenImage(
+            WebContents webContents, String imageUrl, FetchHomescreenImageCallback callback) {
+        nativeFetchHomescreenImage(webContents, imageUrl, callback);
+    }
+
+    /**
+     * Called once the image requested by {@link #fetchHomescreenImage()} is fetched in order to run
+     * the Java callback.
+     */
+    @CalledByNative
+    public static void onFetchedHomescreenImage(
+            Bitmap bitmap, long murmur2Hash, FetchHomescreenImageCallback callback) {
+        callback.onFetchedHomescreenImage(bitmap, murmur2Hash);
+    }
+
+    /**
      * Returns true if WebAPKs are enabled and there is a WebAPK installed which can handle
      * {@link url}.
      */
@@ -578,5 +605,7 @@ public class ShortcutHelper {
         return null;
     }
 
+    private static native void nativeFetchHomescreenImage(
+            WebContents webContents, String imageUrl, FetchHomescreenImageCallback callback);
     private static native void nativeOnWebappDataStored(long callbackPointer);
 }