Tell java side when the native auth handler is gone

android_webview/java/src/org/chromium/android_webview/AwHttpAuthHandler.java

Index: android_webview/java/src/org/chromium/android_webview/AwHttpAuthHandler.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwHttpAuthHandler.java b/android_webview/java/src/org/chromium/android_webview/AwHttpAuthHandler.java
index a7fc3393eb16f937fe5abe587f3969777bca13d2..5e5a9f1a45c6c74d36ac9f332624c348029fa543 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwHttpAuthHandler.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwHttpAuthHandler.java
@@ -11,14 +11,20 @@ import org.chromium.base.JNINamespace;
 public class AwHttpAuthHandler {
 
     private int mNativeAwHttpAuthHandler;
-    private boolean mFirstAttempt;
+    private final boolean mFirstAttempt;
 
     public void proceed(String username, String password) {
-        nativeProceed(mNativeAwHttpAuthHandler, username, password);
+        if (mNativeAwHttpAuthHandler != 0) {
+            nativeProceed(mNativeAwHttpAuthHandler, username, password);
+            mNativeAwHttpAuthHandler = 0;
+        }
     }
 
     public void cancel() {
-        nativeCancel(mNativeAwHttpAuthHandler);
+        if (mNativeAwHttpAuthHandler != 0) {
+            nativeCancel(mNativeAwHttpAuthHandler);
+            mNativeAwHttpAuthHandler = 0;
+        }
     }
 
     public boolean isFirstAttempt() {
@@ -35,6 +41,11 @@ public class AwHttpAuthHandler {
         mFirstAttempt = firstAttempt;
     }
 
+    @CalledByNative
+    void handlerDestroyed() {
+        mNativeAwHttpAuthHandler = 0;
+    }
+
     private native void nativeProceed(int nativeAwHttpAuthHandler,
             String username, String password);
     private native void nativeCancel(int nativeAwHttpAuthHandler);