[Android WebView] Synthesize a fake page loading event on page source modification

When a script modifies page source of a non-committed page, we need to
notify clients, so they can update the URL bar to avoid confusion.

BUG=458569

Review URL: https://codereview.chromium.org/924833003

Cr-Commit-Position: refs/heads/master@{#318222}

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

@@ -1239,6 +1239,19 @@ public class AwContents implements SmartClipProvider,
         return url;
     }
 
+    /**
+     * Gets the last committed URL. It represents the current page that is
+     * displayed in WebContents. It represents the current security context.
+     *
+     * @return The URL of the current page or null if it's empty.
+     */
+    public String getLastCommittedUrl() {
+        if (isDestroyed()) return null;
+        String url = mWebContents.getLastCommittedUrl();
+        if (url == null || url.trim().isEmpty()) return null;
+        return url;
+    }
+
     public void requestFocus() {
         mAwViewMethods.requestFocus();
     }
@@ -1831,6 +1844,11 @@ public class AwContents implements SmartClipProvider,
         return ports;
     }
 
+    public boolean hasAccessedInitialDocument() {
+        if (isDestroyed()) return false;
+        return mWebContents.hasAccessedInitialDocument();
+    }
+
     //--------------------------------------------------------------------------------------------
     //  View and ViewGroup method implementations
     //--------------------------------------------------------------------------------------------

android_webview/java/src/org/chromium/android_webview/AwWebContentsDelegate.java

@@ -37,4 +37,8 @@ public abstract class AwWebContentsDelegate extends WebContentsDelegateAndroid {
     // Call in response to a prior runFileChooser call.
     protected static native void nativeFilesSelectedInChooser(int processId, int renderId,
             int modeFlags, String[] filePath, String[] displayName);
+
+    @Override
+    @CalledByNative
+    public abstract void navigationStateChanged(int flags);
 }

android_webview/java/src/org/chromium/android_webview/AwWebContentsDelegateAdapter.java

@@ -11,6 +11,7 @@ import android.os.AsyncTask;
 import android.os.Handler;
 import android.os.Message;
 import android.provider.MediaStore;
+import android.text.TextUtils;
 import android.util.Log;
 import android.view.KeyEvent;
 import android.view.View;
@@ -19,6 +20,7 @@ import android.webkit.ValueCallback;
 
 import org.chromium.base.ContentUriUtils;
 import org.chromium.base.ThreadUtils;
+import org.chromium.content_public.browser.InvalidateTypes;
 
 /**
  * Adapts the AwWebContentsDelegate interface to the AwContentsClient interface.
@@ -212,6 +214,20 @@ class AwWebContentsDelegateAdapter extends AwWebContentsDelegate {
         mContentsClient.onRequestFocus();
     }
 
+    @Override
+    public void navigationStateChanged(int flags) {
+        if ((flags & InvalidateTypes.URL) != 0 && mAwContents.hasAccessedInitialDocument()) {
+            // Hint the client to show the last committed url, as it may be unsafe to show
+            // the pending entry.
+            String url = mAwContents.getLastCommittedUrl();
+            url = TextUtils.isEmpty(url) ? "about:blank" : url;
+            mContentsClient.onPageStarted(url);
+            mContentsClient.onLoadResource(url);
+            mContentsClient.onProgressChanged(100);
+            mContentsClient.onPageFinished(url);
+        }
+    }
+
     @Override
     public void toggleFullscreenModeForTab(boolean enterFullscreen) {
         if (enterFullscreen) {

android_webview/java_library_common.mk

@@ -55,6 +55,7 @@ $(call intermediates-dir-for,GYP,shared)/enums/console_message_level_java/org/ch
 $(call intermediates-dir-for,GYP,shared)/enums/content_gamepad_mapping/org/chromium/content/browser/input/CanonicalAxisIndex.java \
 $(call intermediates-dir-for,GYP,shared)/enums/content_gamepad_mapping/org/chromium/content/browser/input/CanonicalButtonIndex.java \
 $(call intermediates-dir-for,GYP,shared)/enums/gesture_event_type_java/org/chromium/content/browser/GestureEventType.java \
+$(call intermediates-dir-for,GYP,shared)/enums/invalidate_types_java/org/chromium/content_public/browser/InvalidateTypes.java \
 $(call intermediates-dir-for,GYP,shared)/enums/navigation_controller_java/org/chromium/content_public/browser/navigation_controller/LoadURLType.java \
 $(call intermediates-dir-for,GYP,shared)/enums/navigation_controller_java/org/chromium/content_public/browser/navigation_controller/UserAgentOverrideOption.java \
 $(call intermediates-dir-for,GYP,shared)/enums/popup_item_type_java/org/chromium/content/browser/input/PopupItemType.java \

android_webview/javatests/src/org/chromium/android_webview/test/PopupWindowTest.java

@@ -5,13 +5,14 @@
 package org.chromium.android_webview.test;
 
 import android.os.Build;
-import android.test.suitebuilder.annotation.SmallTest;
+import android.test.suitebuilder.annotation.MediumTest;
 
 import org.chromium.android_webview.AwContents;
 import org.chromium.android_webview.test.util.AwTestTouchUtils;
 import org.chromium.android_webview.test.util.CommonResources;
 import org.chromium.base.test.util.Feature;
 import org.chromium.base.test.util.MinAndroidSdkLevel;
+import org.chromium.content.browser.test.util.TestCallbackHelperContainer;
 import org.chromium.net.test.util.TestWebServer;
 
 import java.util.concurrent.Callable;
@@ -38,6 +39,9 @@ public class PopupWindowTest extends AwTestBase {
         mParentContentsClient = new TestAwContentsClient();
         mParentContainerView = createAwTestContainerViewOnMainSync(mParentContentsClient);
         mParentContents = mParentContainerView.getAwContents();
+        mPopupContentsClient = new TestAwContentsClient();
+        mPopupContainerView = createAwTestContainerViewOnMainSync(mPopupContentsClient);
+        mPopupContents = mPopupContainerView.getAwContents();
         mWebServer = TestWebServer.start();
     }
 
@@ -49,7 +53,9 @@ public class PopupWindowTest extends AwTestBase {
         super.tearDown();
     }
 
-    private void triggerPopup() throws Throwable {
+    // It is expected that the parent page contains a link that opens a popup window,
+    // and the test server is already pre-loaded with both parent and popup pages.
+    private void triggerPopup(String parentUrl) throws Throwable {
         enableJavaScriptOnUiThread(mParentContents);
         getInstrumentation().runOnMainSync(new Runnable() {
             @Override
@@ -59,21 +65,6 @@ public class PopupWindowTest extends AwTestBase {
             }
         });
 
-        final String popupPath = "/popup.html";
-
-        final String parentPageHtml = CommonResources.makeHtmlPageFrom("",
-                "<script>"
-                        + "function tryOpenWindow() {"
-                        + "  var newWindow = window.open('" + popupPath + "');"
-                        + "}</script>"
-                        + "<a class=\"full_view\" onclick=\"tryOpenWindow();\">Click me!</a>");
-        final String popupPageHtml = CommonResources.makeHtmlPageFrom(
-                "<title>" + POPUP_TITLE + "</title>",
-                "This is a popup window");
-
-        final String parentUrl = mWebServer.setResponse("/popupParent.html", parentPageHtml, null);
-        mWebServer.setResponse(popupPath, popupPageHtml, null);
-
         mParentContentsClient.getOnCreateWindowHelper().setReturnValue(true);
         loadUrlSync(mParentContents,
                     mParentContentsClient.getOnPageFinishedHelper(),
@@ -88,10 +79,6 @@ public class PopupWindowTest extends AwTestBase {
     }
 
     private void connectPendingPopup() throws Exception {
-        mPopupContentsClient = new TestAwContentsClient();
-        mPopupContainerView = createAwTestContainerViewOnMainSync(mPopupContentsClient);
-        mPopupContents = mPopupContainerView.getAwContents();
-
         getInstrumentation().runOnMainSync(new Runnable() {
             @Override
             public void run() {
@@ -100,10 +87,22 @@ public class PopupWindowTest extends AwTestBase {
         });
     }
 
-    @SmallTest
+    @MediumTest
     @Feature({"AndroidWebView"})
     public void testPopupWindow() throws Throwable {
-        triggerPopup();
+        final String popupPath = "/popup.html";
+        final String parentPageHtml = CommonResources.makeHtmlPageFrom("",
+                "<script>"
+                + "function tryOpenWindow() {"
+                + "  var newWindow = window.open('" + popupPath + "');"
+                + "}</script>"
+                + "<a class=\"full_view\" onclick=\"tryOpenWindow();\">Click me!</a>");
+        final String popupPageHtml = CommonResources.makeHtmlPageFrom(
+                "<title>" + POPUP_TITLE + "</title>",
+                "This is a popup window");
+        final String parentUrl = mWebServer.setResponse("/popupParent.html", parentPageHtml, null);
+        mWebServer.setResponse(popupPath, popupPageHtml, null);
+        triggerPopup(parentUrl);
         connectPendingPopup();
         poll(new Callable<Boolean>() {
             @Override
@@ -112,4 +111,33 @@ public class PopupWindowTest extends AwTestBase {
             }
         });
     }
+
+    @MediumTest
+    @Feature({"AndroidWebView"})
+    public void testOnPageFinishedCalledAfterModifyingPageSource() throws Throwable {
+        final String popupPath = "/popup.html";
+        final String popupUrl = mWebServer.setResponseWithNoContentStatus(popupPath);
+        final String parentHtml = CommonResources.makeHtmlPageFrom("",
+                "<script>"
+                + "function tryOpenWindow() {"
+                + "  window.popupWindow = window.open('" + popupPath + "');"
+                + "}"
+                + "function modifyDomOfPopup() {"
+                + "  window.popupWindow.document.body.innerHTML = 'Hello from the parent!';"
+                + "}</script>"
+                + "<a class='full_view' onclick='tryOpenWindow();'>Click me!</a>");
+        final String parentUrl = mWebServer.setResponse("/parent.html", parentHtml, null);
+        triggerPopup(parentUrl);
+        TestCallbackHelperContainer.OnPageFinishedHelper onPageFinishedHelper =
+                mPopupContentsClient.getOnPageFinishedHelper();
+        int onPageFinishedCallCount = onPageFinishedHelper.getCallCount();
+        connectPendingPopup();
+        onPageFinishedHelper.waitForCallback(onPageFinishedCallCount);
+
+        onPageFinishedCallCount = onPageFinishedHelper.getCallCount();
+        executeJavaScriptAndWaitForResult(mParentContents, mParentContentsClient,
+                "modifyDomOfPopup()");
+        onPageFinishedHelper.waitForCallback(onPageFinishedCallCount);
+        assertEquals("about:blank", onPageFinishedHelper.getUrl());
+    }
 }

android_webview/libwebviewchromium.gypi

@@ -23,6 +23,7 @@
         '../content/content.gyp:console_message_level_java',
         '../content/content.gyp:content_gamepad_mapping',
         '../content/content.gyp:gesture_event_type_java',
+        '../content/content.gyp:invalidate_types_java',
         '../content/content.gyp:navigation_controller_java',
         '../content/content.gyp:popup_item_type_java',
         '../content/content.gyp:result_codes_java',

android_webview/native/aw_web_contents_delegate.cc

@@ -163,6 +163,18 @@ void AwWebContentsDelegate::AddNewContents(WebContents* source,
   }
 }
 
+void AwWebContentsDelegate::NavigationStateChanged(
+    content::WebContents* source,
+    content::InvalidateTypes changed_flags) {
+  JNIEnv* env = AttachCurrentThread();
+
+  ScopedJavaLocalRef<jobject> java_delegate = GetJavaDelegate(env);
+  if (java_delegate.obj()) {
+    Java_AwWebContentsDelegate_navigationStateChanged(env, java_delegate.obj(),
+                                                      changed_flags);
+  }
+}
+
 // Notifies the delegate about the creation of a new WebContents. This
 // typically happens when popups are created.
 void AwWebContentsDelegate::WebContentsCreated(

android_webview/native/aw_web_contents_delegate.h

@@ -40,6 +40,8 @@ class AwWebContentsDelegate
                       bool user_gesture,
                       bool* was_blocked) override;
 
+  void NavigationStateChanged(content::WebContents* source,
+                              content::InvalidateTypes changed_flags) override;
   void WebContentsCreated(content::WebContents* source_contents,
                           int opener_render_frame_id,
                           const base::string16& frame_name,

chrome/android/java/src/org/chromium/chrome/browser/Tab.java

@@ -49,6 +49,7 @@ import org.chromium.content.browser.ContentView;
 import org.chromium.content.browser.ContentViewClient;
 import org.chromium.content.browser.ContentViewCore;
 import org.chromium.content.browser.WebContentsObserver;
+import org.chromium.content_public.browser.InvalidateTypes;
 import org.chromium.content_public.browser.LoadUrlParams;
 import org.chromium.content_public.browser.WebContents;
 import org.chromium.content_public.common.Referrer;
@@ -387,10 +388,10 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
 
         @Override
         public void navigationStateChanged(int flags) {
-            if ((flags & INVALIDATE_TYPE_TITLE) != 0) {
+            if ((flags & InvalidateTypes.TITLE) != 0) {
                 for (TabObserver observer : mObservers) observer.onTitleUpdated(Tab.this);
             }
-            if ((flags & INVALIDATE_TYPE_URL) != 0) {
+            if ((flags & InvalidateTypes.URL) != 0) {
                 for (TabObserver observer : mObservers) observer.onUrlUpdated(Tab.this);
             }
         }

components/web_contents_delegate_android/android/java/src/org/chromium/components/web_contents_delegate_android/WebContentsDelegateAndroid.java

@@ -8,6 +8,7 @@ import android.view.KeyEvent;
 
 import org.chromium.base.CalledByNative;
 import org.chromium.base.JNINamespace;
+import org.chromium.content_public.browser.InvalidateTypes;
 import org.chromium.content_public.browser.WebContents;
 
 /**
@@ -25,16 +26,8 @@ public class WebContentsDelegateAndroid {
     // Equivalent of WebCore::WebConsoleMessage::LevelError.
     public static final int LOG_LEVEL_ERROR = 3;
 
-    // Flags passed to the WebContentsDelegateAndroid.navigationStateChanged to tell it
-    // what has changed. Should match the values in invalidate_type.h.
-    // Equivalent of InvalidateTypes::INVALIDATE_TYPE_URL.
-    public static final int INVALIDATE_TYPE_URL = 1 << 0;
-    // Equivalent of InvalidateTypes::INVALIDATE_TYPE_TAB.
-    public static final int INVALIDATE_TYPE_TAB = 1 << 1;
-    // Equivalent of InvalidateTypes::INVALIDATE_TYPE_LOAD.
-    public static final int INVALIDATE_TYPE_LOAD = 1 << 2;
-    // Equivalent of InvalidateTypes::INVALIDATE_TYPE_TITLE.
-    public static final int INVALIDATE_TYPE_TITLE = 1 << 3;
+    // TODO(mnaganov): Remove after getting rid of downstream usages.
+    public static final int INVALIDATE_TYPE_TAB = InvalidateTypes.TAB;
 
     // The most recent load progress callback received from WebContents, as a percentage.
     // Initialize to 100 to indicate that we're not in a loading state.

content/browser/web_contents/web_contents_android.cc

@@ -170,6 +170,14 @@ ScopedJavaLocalRef<jstring> WebContentsAndroid::GetURL(JNIEnv* env,
   return ConvertUTF8ToJavaString(env, web_contents_->GetURL().spec());
 }
 
+ScopedJavaLocalRef<jstring> WebContentsAndroid::GetLastCommittedURL(
+    JNIEnv* env,
+    jobject) const {
+  return ConvertUTF8ToJavaString(env,
+                                 web_contents_->GetLastCommittedURL().spec());
+}
+
+
 jboolean WebContentsAndroid::IsIncognito(JNIEnv* env, jobject obj) {
   return web_contents_->GetBrowserContext()->IsOffTheRecord();
 }
@@ -480,4 +488,11 @@ void WebContentsAndroid::AddMessageToDevToolsConsole(JNIEnv* env,
       ConvertJavaStringToUTF8(env, message)));
 }
 
+jboolean WebContentsAndroid::HasAccessedInitialDocument(
+    JNIEnv* env,
+    jobject jobj) {
+  return static_cast<content::WebContentsImpl*>(web_contents_)->
+      HasAccessedInitialDocument();
+}
+
 }  // namespace content

content/browser/web_contents/web_contents_android.h

@@ -50,6 +50,8 @@ class CONTENT_EXPORT WebContentsAndroid
   void Stop(JNIEnv* env, jobject obj);
   jint GetBackgroundColor(JNIEnv* env, jobject obj);
   base::android::ScopedJavaLocalRef<jstring> GetURL(JNIEnv* env, jobject) const;
+  base::android::ScopedJavaLocalRef<jstring> GetLastCommittedURL(JNIEnv* env,
+                                                                 jobject) const;
   jboolean IsIncognito(JNIEnv* env, jobject obj);
 
   void ResumeResponseDeferredAtStart(JNIEnv* env, jobject obj);
@@ -109,6 +111,8 @@ class CONTENT_EXPORT WebContentsAndroid
                                    jint level,
                                    jstring message);
 
+  jboolean HasAccessedInitialDocument(JNIEnv* env, jobject jobj);
+
  private:
   RenderWidgetHostViewAndroid* GetRenderWidgetHostViewAndroid();
 

content/content.gyp

@@ -443,6 +443,7 @@
             'content_strings_grd',
             'content_gamepad_mapping',
             'gesture_event_type_java',
+            'invalidate_types_java',
             'navigation_controller_java',
             'popup_item_type_java',
             'result_codes_java',
@@ -494,6 +495,14 @@
           },
           'includes': [ '../build/android/java_cpp_enum.gypi' ],
         },
+        {
+          'target_name': 'invalidate_types_java',
+          'type': 'none',
+          'variables': {
+            'source_file': 'public/browser/invalidate_type.h',
+          },
+          'includes': [ '../build/android/java_cpp_enum.gypi' ],
+        },
         {
           'target_name': 'navigation_controller_java',
           'type': 'none',

content/public/android/BUILD.gn

@@ -110,6 +110,7 @@ java_cpp_enum("content_public_android_java_enums_srcjar") {
     "//content/browser/android/content_view_core_impl.cc",
     "//content/browser/android/gesture_event_type.h",
     "//content/browser/gamepad/gamepad_standard_mappings.h",
+    "//content/public/browser/invalidate_type.h",
     "//content/public/browser/navigation_controller.h",
     "//content/public/common/console_message_level.h",
     "//content/public/common/result_codes.h",
@@ -122,6 +123,7 @@ java_cpp_enum("content_public_android_java_enums_srcjar") {
     "org/chromium/content/browser/input/CanonicalAxisIndex.java",
     "org/chromium/content/browser/input/CanonicalButtonIndex.java",
     "org/chromium/content/browser/input/PopupItemType.java",
+    "org/chromium/content_public/browser/InvalidateTypes.java",
     "org/chromium/content_public/browser/navigation_controller/LoadURLType.java",
     "org/chromium/content_public/browser/navigation_controller/UserAgentOverrideOption.java",
     "org/chromium/content_public/common/ConsoleMessageLevel.java",

content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsImpl.java

@@ -165,6 +165,11 @@ import org.chromium.content_public.browser.WebContents;
         return nativeGetURL(mNativeWebContentsAndroid);
     }
 
+    @Override
+    public String getLastCommittedUrl() {
+        return nativeGetLastCommittedURL(mNativeWebContentsAndroid);
+    }
+
     @Override
     public boolean isIncognito() {
         return nativeIsIncognito(mNativeWebContentsAndroid);
@@ -296,6 +301,11 @@ import org.chromium.content_public.browser.WebContents;
         nativeAddMessageToDevToolsConsole(mNativeWebContentsAndroid, level, message);
     }
 
+    @Override
+    public boolean hasAccessedInitialDocument() {
+        return nativeHasAccessedInitialDocument(mNativeWebContentsAndroid);
+    }
+
     @CalledByNative
     private static void onEvaluateJavaScriptResult(
             String jsonResult, JavaScriptCallback callback) {
@@ -328,6 +338,7 @@ import org.chromium.content_public.browser.WebContents;
     private native void nativeScrollFocusedEditableNodeIntoView(long nativeWebContentsAndroid);
     private native void nativeSelectWordAroundCaret(long nativeWebContentsAndroid);
     private native String nativeGetURL(long nativeWebContentsAndroid);
+    private native String nativeGetLastCommittedURL(long nativeWebContentsAndroid);
     private native boolean nativeIsIncognito(long nativeWebContentsAndroid);
     private native void nativeResumeResponseDeferredAtStart(long nativeWebContentsAndroid);
     private native void nativeSetHasPendingNavigationTransitionForTesting(
@@ -347,4 +358,6 @@ import org.chromium.content_public.browser.WebContents;
             String script, JavaScriptCallback callback);
     private native void nativeAddMessageToDevToolsConsole(
             long nativeWebContentsAndroid, int level, String message);
+    private native boolean nativeHasAccessedInitialDocument(
+            long nativeWebContentsAndroid);
 }

content/public/android/java/src/org/chromium/content_public/browser/WebContents.java

@@ -138,6 +138,14 @@ public interface WebContents {
      */
     public String getUrl();
 
+    /**
+     * Gets the last committed URL. It represents the current page that is
+     * displayed in this WebContents. It represents the current security context.
+     *
+     * @return The last committed URL.
+     */
+    public String getLastCommittedUrl();
+
     /**
      * Get the InCognito state of WebContents.
      *
@@ -213,4 +221,12 @@ public interface WebContents {
      * org.chromium.content_public.common.ConsoleMessageLevel.
      */
     public void addMessageToDevToolsConsole(int level, String message);
+
+    /**
+     * Returns whether the initial empty page has been accessed by a script from another
+     * page. Always false after the first commit.
+     *
+     * @return Whether the initial empty page has been accessed by a script.
+     */
+    public boolean hasAccessedInitialDocument();
 }

content/public/browser/invalidate_type.h

@@ -9,6 +9,11 @@ namespace content {
 
 // Flags passed to the WebContentsDelegate.NavigationStateChanged to tell it
 // what has changed. Combine them to update more than one thing.
+//
+// A Java counterpart will be generated for this enum.
+// GENERATED_JAVA_ENUM_PACKAGE: (
+//   org.chromium.content_public.browser)
+// GENERATED_JAVA_PREFIX_TO_STRIP: INVALIDATE_TYPE_
 enum InvalidateTypes {
   INVALIDATE_TYPE_URL           = 1 << 0,  // The URL has changed.
   INVALIDATE_TYPE_TAB           = 1 << 1,  // The favicon, app icon, or crashed

net/test/android/javatests/src/org/chromium/net/test/util/TestWebServer.java

@@ -80,11 +80,14 @@ public class TestWebServer {
         final boolean mIsRedirect;
         final Runnable mResponseAction;
         final boolean mIsNotFound;
+        final boolean mIsNoContent;
 
         Response(byte[] responseData, List<Pair<String, String>> responseHeaders,
-                boolean isRedirect, boolean isNotFound, Runnable responseAction) {
+                boolean isRedirect, boolean isNotFound, boolean isNoContent,
+                Runnable responseAction) {
             mIsRedirect = isRedirect;
             mIsNotFound = isNotFound;
+            mIsNoContent = isNoContent;
             mResponseData = responseData;
             mResponseHeaders = responseHeaders == null
                     ? new ArrayList<Pair<String, String>>() : responseHeaders;
@@ -208,6 +211,7 @@ public class TestWebServer {
     private static final int RESPONSE_STATUS_NORMAL = 0;
     private static final int RESPONSE_STATUS_MOVED_TEMPORARILY = 1;
     private static final int RESPONSE_STATUS_NOT_FOUND = 2;
+    private static final int RESPONSE_STATUS_NO_CONTENT = 3;
 
     private String setResponseInternal(
             String requestPath, byte[] responseData,
@@ -215,10 +219,12 @@ public class TestWebServer {
             int status) {
         final boolean isRedirect = (status == RESPONSE_STATUS_MOVED_TEMPORARILY);
         final boolean isNotFound = (status == RESPONSE_STATUS_NOT_FOUND);
+        final boolean isNoContent = (status == RESPONSE_STATUS_NO_CONTENT);
 
         synchronized (mLock) {
             mResponseMap.put(requestPath, new Response(
-                    responseData, responseHeaders, isRedirect, isNotFound, responseAction));
+                    responseData, responseHeaders, isRedirect, isNotFound, isNoContent,
+                    responseAction));
             mResponseCountMap.put(requestPath, Integer.valueOf(0));
             mLastRequestMap.put(requestPath, null);
         }
@@ -250,6 +256,19 @@ public class TestWebServer {
                 RESPONSE_STATUS_NOT_FOUND);
     }
 
+    /**
+     * Sets a 204 (no content) response to be returned when a particular request path is passed in.
+     *
+     * @param requestPath The path to respond to.
+     * @return The full URL including the path that should be requested to get the expected
+     *         response.
+     */
+    public String setResponseWithNoContentStatus(
+            String requestPath) {
+        return setResponseInternal(requestPath, "".getBytes(), null, null,
+                RESPONSE_STATUS_NO_CONTENT);
+    }
+
     /**
      * Sets a response to be returned when a particular request path is passed
      * in (with the option to specify additional headers).
@@ -451,6 +470,10 @@ public class TestWebServer {
         } else if (response.mIsNotFound) {
             httpResponse = createResponse(HttpStatus.SC_NOT_FOUND);
             servedResponseFor(path, request);
+        } else if (response.mIsNoContent) {
+            httpResponse = createResponse(HttpStatus.SC_NO_CONTENT);
+            httpResponse.setHeader("Content-Length", "0");
+            servedResponseFor(path, request);
         } else if (response.mIsRedirect) {
             httpResponse = createResponse(HttpStatus.SC_MOVED_TEMPORARILY);
             for (Pair<String, String> header : response.mResponseHeaders) {