Revert of Remove fallback tick software draw.

Revert of Remove fallback tick software draw. (patchset #3 id:100001 of https://codereview.chromium.org/1428263003/ )

Reason for revert:
Causes scheduler to stop activating after clearView is called. PrepareTiles is required to advance the scheduler, so draws are currently needed.

crbug.com/558743

Original issue's description:
> Remove fallback tick software draw.
>
> The fallback software draw was needed to allow the scheduler to advance
> in cases where the WebView is detached or offscreen. Because it is now
> possible for the pending tree to activate without a draw, the fallback
> tick is no longer needed in order for VisualStateListener callbacks
> to fire.
>
> BUG=431166
>
> Committed: https://crrev.com/9addff46d3bc49f8d04e43eeb3f55e01a4982a00
> Cr-Commit-Position: refs/heads/master@{#358156}

TBR=boliu@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=431166
Committed: https://crrev.com/30da41a6f63826d4c7f4a5cd1c14c9ff9ca7258f
Cr-Commit-Position: refs/heads/master@{#361334}

[Tobias Sargeant, 2015-11-24 10:14:44]

Created Revert of Remove fallback tick software draw.

[commit-bot: I haz the power, 2015-11-24 10:15:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1474653002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1474653002/1

[commit-bot: I haz the power, 2015-11-24 10:17:43]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-11-24 10:17:44]

Failed to apply patch for
android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java:
While running git apply --index -3 -p1;
  error: patch failed:
android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java:405
  Falling back to three-way merge...
  Applied patch to
'android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java'
with conflicts.
  U
android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java

Patch:      
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
index
8af193ff1c9698056a47f27fdf5360b737cf8dfb..2ae84a6b203469799177395a7870e94bfd8ab7ef
100644
---
a/android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java
+++
b/android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java
@@ -9,12 +9,13 @@
 import android.graphics.Rect;
 import android.test.suitebuilder.annotation.SmallTest;
 import android.util.Base64;
+import android.view.View;
+import android.webkit.WebChromeClient;
 
 import static org.chromium.base.test.util.ScalableTimeout.scaleTimeout;
 
 import org.chromium.android_webview.AwContents;
 import org.chromium.android_webview.AwContents.VisualStateCallback;
-import org.chromium.android_webview.AwContentsClient;
 import org.chromium.android_webview.AwWebResourceResponse;
 import org.chromium.android_webview.test.util.CommonResources;
 import org.chromium.android_webview.test.util.GraphicsTestUtils;
@@ -31,7 +32,6 @@
 import java.io.IOException;
 import java.io.InputStream;
 
-import java.util.concurrent.Callable;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
@@ -42,8 +42,6 @@
 public class VisualStateTest extends AwTestBase {
     private static final String WAIT_FOR_JS_TEST_URL =
             "file:///android_asset/visual_state_waits_for_js_test.html";
-    private static final String WAIT_FOR_JS_DETACHED_TEST_URL =
-           
"file:///android_asset/visual_state_waits_for_js_detached_test.html";
     private static final String ON_PAGE_COMMIT_VISIBLE_TEST_URL =
            
"file:///android_asset/visual_state_on_page_commit_visible_test.html";
     private static final String FULLSCREEN_TEST_URL =
@@ -405,60 +403,77 @@
         assertTrue(testFinishedSignal.await(AwTestBase.WAIT_TIMEOUT_MS,
TimeUnit.MILLISECONDS));
     }
 
-    private AwTestContainerView createDetachedTestContainerViewOnMainSync(
-            final AwContentsClient awContentsClient) {
-        return ThreadUtils.runOnUiThreadBlockingNoException(new
Callable<AwTestContainerView>() {
-            @Override
-            public AwTestContainerView call() {
-                AwTestContainerView detachedView =
-                        createDetachedAwTestContainerView(awContentsClient);
-                detachedView.setClipBounds(new Rect(0, 0, 100, 100));
-                detachedView.measure(100, 100);
-                detachedView.layout(0, 0, 100, 100);
-                return detachedView;
-            }
-        });
-    }
-
-    @Feature({"AndroidWebView"})
-    @SmallTest
-    public void testVisualStateCallbackWhenContainerViewDetached() throws
Throwable {
+    @Feature({"AndroidWebView"})
+    @SmallTest
+    public void testVisualStateCallbackWhenContainerViewDetached()
+            throws Throwable {
+        final CountDownLatch readyToEnterFullscreenSignal = new
CountDownLatch(1);
+        final CountDownLatch hasCustomViewSignal = new CountDownLatch(1);
         final CountDownLatch testFinishedSignal = new CountDownLatch(1);
 
-        final TestAwContentsClient awContentsClient = new
TestAwContentsClient();
-        final AwTestContainerView testView =
-                createDetachedTestContainerViewOnMainSync(awContentsClient);
+        final AtomicReference<AwContents> awContentsRef = new
AtomicReference<>();
+        final AtomicReference<View> customViewRef = new AtomicReference<>();
+
+        final TestAwContentsClient awContentsClient = new
TestAwContentsClient() {
+            @Override
+            public void onPageFinished(String url) {
+                super.onPageFinished(url);
+                readyToEnterFullscreenSignal.countDown();
+            }
+
+            @Override
+            public void onShowCustomView(
+                    final View customView, WebChromeClient.CustomViewCallback
callback) {
+                // Please note that we don't attach the custom view to the
window here
+                // (awContentsClient is an instance of TestAwContentsClient,
not
+                // FullScreenVideoTestAwContentsClient).
+                customView.setClipBounds(new Rect(0, 0, 100, 100));
+                customView.measure(100, 100);
+                customView.layout(0, 0, 100, 100);
+                customViewRef.set(customView);
+                hasCustomViewSignal.countDown();
+            }
+        };
+        final AwTestContainerView testView =
createAwTestContainerViewOnMainSync(awContentsClient);
         final AwContents awContents = testView.getAwContents();
+        awContentsRef.set(awContents);
         final ContentViewCore contentViewCore = testView.getContentViewCore();
-
         enableJavaScriptOnUiThread(awContents);
-
-        // JS will notify this observer once it has changed the background
color of the page.
-        final Object pageChangeNotifier = new Object() {
-            public void onPageChanged() {
-                ThreadUtils.postOnUiThread(new Runnable() {
-                    @Override
-                    public void run() {
-                        awContents.insertVisualStateCallback(20, new
VisualStateCallback() {
-                            @Override
-                            public void onComplete(long id) {
-                                Bitmap redScreenshot =
-                                       
GraphicsTestUtils.drawAwContents(awContents, 100, 100);
-                                assertEquals(Color.RED,
redScreenshot.getPixel(50, 50));
-                                testFinishedSignal.countDown();
-                            }
-                        });
+        awContents.getSettings().setFullscreenSupported(true);
+
+        // JS will notify this observer once it has entered fullscreen.
+        final JavascriptEventObserver jsObserver = new
JavascriptEventObserver();
+        runTestOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                jsObserver.register(contentViewCore, "jsObserver");
+            }
+        });
+
+        loadUrlSync(awContents, awContentsClient.getOnPageFinishedHelper(),
FULLSCREEN_TEST_URL);
+
+        assertTrue(readyToEnterFullscreenSignal.await(
+                AwTestBase.WAIT_TIMEOUT_MS, TimeUnit.MILLISECONDS));
+        DOMUtils.clickNode(VisualStateTest.this, contentViewCore,
ENTER_FULLSCREEN_CONTROL_ID);
+
+        assertTrue(hasCustomViewSignal.await(AwTestBase.WAIT_TIMEOUT_MS,
TimeUnit.MILLISECONDS));
+        assertTrue(jsObserver.waitForEvent(WAIT_TIMEOUT_MS));
+
+        runTestOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                awContents.insertVisualStateCallback(20, new
VisualStateCallback() {
+                    @Override
+                    public void onComplete(long id) {
+                        assertFalse(customViewRef.get().isAttachedToWindow());
+                        // NOTE: We cannot use drawAwContents here because the
web contents
+                        // are rendered into the custom view while in
fullscreen.
+                        Bitmap redScreenshot = GraphicsTestUtils.drawView(
+                                customViewRef.get(), 100, 100);
+                        assertEquals(Color.RED, redScreenshot.getPixel(50,
50));
+                        testFinishedSignal.countDown();
                     }
                 });
-            }
-        };
-
-        runTestOnUiThread(new Runnable() {
-            @Override
-            public void run() {
-                contentViewCore.addPossiblyUnsafeJavascriptInterface(
-                        pageChangeNotifier, "pageChangeNotifier", null);
-                awContents.loadUrl(WAIT_FOR_JS_DETACHED_TEST_URL);
             }
         });

[commit-bot: I haz the power, 2015-11-24 10:19:16]

The CQ bit was unchecked by commit-bot@chromium.org

[Tobias Sargeant, 2015-11-24 14:08:49]

The CQ bit was checked by tobiasjs@chromium.org

[commit-bot: I haz the power, 2015-11-24 14:09:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1474653002/160001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1474653002/160001

[commit-bot: I haz the power, 2015-11-24 14:09:54]

Committed patchset #2 (id:160001)

[commit-bot: I haz the power, 2015-11-24 14:10:59]

Patchset 2 (id:??) landed as
https://crrev.com/30da41a6f63826d4c7f4a5cd1c14c9ff9ca7258f
Cr-Commit-Position: refs/heads/master@{#361334}