aw: Cancel pending callbacks after native destroy

android_webview/java/src/org/chromium/android_webview/AwContents.java

Index: android_webview/java/src/org/chromium/android_webview/AwContents.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwContents.java b/android_webview/java/src/org/chromium/android_webview/AwContents.java
index 030a0a55bf0a10e9dbe748bc7c357e23b0e7f600..d1fd8e74faeeb7bbfcca9b46555fcc480a94e0bf 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContents.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContents.java
@@ -755,6 +755,13 @@ public class AwContents implements SmartClipProvider,
         mInitialFunctor = new AwGLFunctor(mNativeDrawGLFunctorFactory, mContainerView);
         mCurrentFunctor = mInitialFunctor;
         mContentsClient = contentsClient;
+        mContentsClient.getCallbackHelper().setCancelCallbackPoller(
+                new AwContentsClientCallbackHelper.CancelCallbackPoller() {
+                    @Override
+                    public boolean cancelAllCallbacks() {
+                        return AwContents.this.isDestroyed(NO_WARN);
+                    }
+                });
         mAwViewMethods = new AwViewMethodsImpl();
         mFullScreenTransitionsState = new FullScreenTransitionsState(
                 mContainerView, mInternalAccessAdapter, mAwViewMethods);
@@ -1211,12 +1218,7 @@ public class AwContents implements SmartClipProvider,
      * @return whether this instance of WebView is flagged as destroyed.
      */
     private boolean isDestroyed(int warnIfDestroyed) {
-        if (!mIsDestroyed) {
-            assert mContentViewCore != null;
-            assert mWebContents != null;
-            assert mNavigationController != null;
-            assert mNativeAwContents != 0;
-        } else if (warnIfDestroyed == WARN) {
+        if (mIsDestroyed && warnIfDestroyed == WARN) {
             Log.w(TAG, "Application attempted to call on a destroyed WebView", new Throwable());
         }
         boolean destroyRunnableHasRun =