Fixing NPE crash when the google3 implementation isn't available.

Bug: 1149344, 1128269
Change-Id: I471ddf82d612de72085629ddaeb29c68b48d6f91
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2542159
Commit-Queue: Jonathan Freed <freedjm@chromium.org>
Commit-Queue: Dan H <harringtond@chromium.org>
Reviewed-by: Dan H <harringtond@chromium.org>
Auto-Submit: Jonathan Freed <freedjm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827945}

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/v2/FeedServiceBridge.java

@@ -12,6 +12,7 @@ import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.annotations.NativeMethods;
 import org.chromium.chrome.browser.AppHooks;
 import org.chromium.chrome.browser.feed.library.common.locale.LocaleUtils;
+import org.chromium.chrome.browser.xsurface.ImagePrefetcher;
 import org.chromium.chrome.browser.xsurface.ProcessScope;
 /**
  * Bridge for FeedService-related calls.
@@ -52,7 +53,13 @@ public final class FeedServiceBridge {
 
     @CalledByNative
     public static void prefetchImage(String url) {
-        xSurfaceProcessScope().provideImagePrefetcher().prefetchImage(url);
+        ProcessScope processScope = xSurfaceProcessScope();
+        if (processScope != null) {
+            ImagePrefetcher imagePrefetcher = processScope.provideImagePrefetcher();
+            if (imagePrefetcher != null) {
+                imagePrefetcher.prefetchImage(url);
+            }
+        }
     }
 
     /** Called at startup to trigger creation of |FeedService|. */