Make AwContents.destroy() idempotent

Follow-up to crrev.com/206516
As mCleanupReference is nulled out in destroy() it now must be
null-checked to allow repeat calls to destroy().

BUG=

Review URL: https://chromiumcodereview.appspot.com/17301002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@207035 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 13 insertions, 11 deletions

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 49fb2d0..8cd9520 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContents.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContents.java
@@ -462,7 +462,7 @@ public class AwContents {
         // methods are called on it after it's been destroyed, and other
         // code relies on AwContents.mContentViewCore to be non-null.
 
-        mCleanupReference.cleanupNow();
+        if (mCleanupReference != null) mCleanupReference.cleanupNow();
         mNativeAwContents = 0;
         mCleanupReference = null;
     }
diff --git a/android_webview/javatests/src/org/chromium/android_webview/test/AwContentsTest.java b/android_webview/javatests/src/org/chromium/android_webview/test/AwContentsTest.java
index 7b29de8..30cfc0c 100644
--- a/android_webview/javatests/src/org/chromium/android_webview/test/AwContentsTest.java
+++ b/android_webview/javatests/src/org/chromium/android_webview/test/AwContentsTest.java
@@ -111,6 +111,18 @@ public class AwContentsTest extends AwTestBase {
         createAwTestContainerView(mContentsClient).getAwContents().destroy();
     }
 
+    @SmallTest
+    @Feature({"AndroidWebView"})
+    public void testCreateLoadPageDestroy() throws Throwable {
+        AwTestContainerView awTestContainerView =
+                createAwTestContainerViewOnMainSync(mContentsClient);
+        loadUrlSync(awTestContainerView.getAwContents(),
+                mContentsClient.getOnPageFinishedHelper(), CommonResources.ABOUT_HTML);
+        destroyAwContentsOnMainSync(awTestContainerView.getAwContents());
+        // It should be safe to call destroy multiple times.
+        destroyAwContentsOnMainSync(awTestContainerView.getAwContents());
+    }
+
     /*
      * @LargeTest
      * @Feature({"AndroidWebView"})
@@ -347,14 +359,4 @@ public class AwContentsTest extends AwTestBase {
             if (webServer != null) webServer.shutdown();
         }
     }
-
-    @SmallTest
-    @Feature({"AndroidWebView"})
-    public void testCreateLoadPageDestroy() throws Throwable {
-        AwTestContainerView awTestContainerView =
-                createAwTestContainerViewOnMainSync(mContentsClient);
-        loadUrlSync(awTestContainerView.getAwContents(),
-                mContentsClient.getOnPageFinishedHelper(), CommonResources.ABOUT_HTML);
-        awTestContainerView.destroy();
-    }
 }