[WebView] Add a new flushVisualState API to AwContents.

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

Index: android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java
diff --git a/android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java b/android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java
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index 0000000000000000000000000000000000000000..a20ddb5f79f5cd14367042c38f9a22a2c0bfb6bc
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+++ b/android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java
@@ -0,0 +1,117 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.android_webview.test;
+
+import android.graphics.Bitmap;
+import android.graphics.Color;
+import android.test.suitebuilder.annotation.SmallTest;
+
+import org.chromium.android_webview.AwContents;
+import org.chromium.android_webview.AwContents.VisualStateFlushCallback;
+import org.chromium.android_webview.test.util.CommonResources;
+import org.chromium.android_webview.test.util.GraphicsTestUtils;
+import org.chromium.base.test.util.Feature;
+import org.chromium.content.browser.test.util.CallbackHelper;
+import org.chromium.content_public.browser.LoadUrlParams;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Visual state related tests.
+ */
+public class VisualStateTest extends AwTestBase {
+
+    private TestAwContentsClient mContentsClient = new TestAwContentsClient();
+
+    @Feature({"AndroidWebView"})
+    @SmallTest
+    public void testFlushVisualStateCallbackIsReceived() throws Throwable {
+        AwTestContainerView testContainer = createAwTestContainerViewOnMainSync(mContentsClient);
+        final AwContents awContents = testContainer.getAwContents();
+        loadUrlSync(
+                awContents, mContentsClient.getOnPageFinishedHelper(), CommonResources.ABOUT_HTML);
+        final CallbackHelper ch = new CallbackHelper();
+        final int chCount = ch.getCallCount();
+        runTestOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                awContents.flushVisualState(new AwContents.VisualStateFlushCallback() {
+                    @Override
+                    public void onComplete() {
+                        ch.notifyCalled();
+                    }
+
+                    @Override
+                    public void onFailure() {
+                        fail("onFailure received");
+                    }
+                });
+            }
+        });
+        ch.waitForCallback(chCount);
+    }
+
+    @Feature({"AndroidWebView"})
+    @SmallTest
+    public void testFlushVisualStateCallbackWaitsForContentsToBeOnScreen() throws Throwable {
+        // This test loads a page with a blue background color. It then waits for the DOM tree
+        // in blink to contain the contents of the blue page (which happens when the onPageFinished
+        // event is received). It then flushes the contents and verifies that the blue page
+        // background color is drawn when the flush callback is received.
+        final LoadUrlParams bluePageUrl = createTestPageUrl("blue");
+        final CountDownLatch testFinishedSignal = new CountDownLatch(1);
+
+        final AtomicReference<AwContents> awContentsRef = new AtomicReference<>();
+        final AwTestContainerView testView =
+                createAwTestContainerViewOnMainSync(new TestAwContentsClient() {
+                    @Override
+                    public void onPageFinished(String url) {
+                        if (bluePageUrl.getUrl().equals(url)) {
+                            awContentsRef.get().flushVisualState(new VisualStateFlushCallback() {
+                                @Override
+                                public void onFailure() {
+                                    fail("onFailure received");
+                                }
+
+                                @Override
+                                public void onComplete() {
+                                    Bitmap blueScreenshot = GraphicsTestUtils.drawAwContents(
+                                            awContentsRef.get(), 1, 1);
+                                    assertEquals(Color.BLUE, blueScreenshot.getPixel(0, 0));
+                                    testFinishedSignal.countDown();
+                                }
+                            });
+                        }
+                    }
+                });
+        final AwContents awContents = testView.getAwContents();
+        awContentsRef.set(awContents);
+
+        runTestOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                awContents.setBackgroundColor(Color.RED);
+                awContents.loadUrl(bluePageUrl);
+
+                // We have just loaded the blue page, but the graphics pipeline is asynchronous
+                // so at this point the WebView still draws red, ie. the View background color.
+                // Only when the flush callback is received will we know for certain that the
+                // blue page contents are on screen.
+                Bitmap redScreenshot = GraphicsTestUtils.drawAwContents(
+                        awContentsRef.get(), 1, 1);
+                assertEquals(Color.RED, redScreenshot.getPixel(0, 0));
+            }
+        });
+
+        assertTrue(testFinishedSignal.await(AwTestBase.WAIT_TIMEOUT_MS, TimeUnit.MILLISECONDS));
+    }
+
+    private static final LoadUrlParams createTestPageUrl(String backgroundColor) {
+        return LoadUrlParams.createLoadDataParams(
+                "<html><body bgcolor=" + backgroundColor + "></body></html>", "text/html", false);
+    }
+}