Use a resource throttle to implement shouldOverrideUrlLoading.

android_webview/java/src/org/chromium/android_webview/AwWebContentsObserver.java

Index: android_webview/java/src/org/chromium/android_webview/AwWebContentsObserver.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwWebContentsObserver.java b/android_webview/java/src/org/chromium/android_webview/AwWebContentsObserver.java
index ec722f61372f5a2262e32a713e3ac8c725235a1a..439dcdfa34ce97d7775e62e3f9d885f21a949db4 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwWebContentsObserver.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwWebContentsObserver.java
@@ -43,16 +43,22 @@ public class AwWebContentsObserver extends WebContentsObserver {
     }
 
     @Override
-    public void didFailLoad(boolean isProvisionalLoad,
-            boolean isMainFrame, int errorCode, String description, String failingUrl) {
+    public void didFailLoad(boolean isProvisionalLoad, boolean isMainFrame, int errorCode,
+            String description, String failingUrl, boolean wasIgnoredByHandler) {
         AwContentsClient client = mAwContentsClient.get();
         if (client == null) return;
         String unreachableWebDataUrl = AwContentsStatics.getUnreachableWebDataUrl();
         boolean isErrorUrl =
                 unreachableWebDataUrl != null && unreachableWebDataUrl.equals(failingUrl);
-        if (isMainFrame && !isErrorUrl && errorCode == NetError.ERR_ABORTED) {
+        if (isMainFrame
+                && !isErrorUrl
+                && errorCode == NetError.ERR_ABORTED
+                && !wasIgnoredByHandler) {
             // Need to call onPageFinished for backwards compatibility with the classic webview.
             // See also AwContents.IoThreadClientImpl.onReceivedError.
+            // If the navigation was ignored because of shouldOverrideUrlLoading we have already
+            // called onPageFinished in
+            // AwContents.InterceptNavigationDelegateImpl.shouldIgnoreNavigation instead.
             client.onPageFinished(failingUrl);
         }
     }