Implement detaching the TabModelSelector from the CompositorViewHolder

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java

Index: chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java b/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java
index a1cee75f88235dd5ad9cc3769c901c3d5cebdd4f..5bc8e11d0d38d0dc024ccaf958b3d388387483ec 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTest.java
@@ -10,15 +10,27 @@ import static org.chromium.chrome.test.util.ChromeRestriction.RESTRICTION_TYPE_N
 import android.content.pm.ActivityInfo;
 import android.support.test.filters.MediumTest;
 import android.support.test.filters.SmallTest;
+import android.view.ViewGroup;
 
+import org.chromium.base.ThreadUtils;
 import org.chromium.base.test.util.CommandLineFlags;
 import org.chromium.base.test.util.Feature;
 import org.chromium.base.test.util.FlakyTest;
 import org.chromium.base.test.util.Restriction;
+import org.chromium.base.test.util.RetryOnFailure;
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.compositor.CompositorViewHolder;
+import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.test.ChromeTabbedActivityTestBase;
 import org.chromium.chrome.test.util.RenderUtils.ViewRenderer;
+import org.chromium.content.browser.ContentViewCore;
+import org.chromium.content.browser.test.util.Criteria;
+import org.chromium.content.browser.test.util.CriteriaHelper;
 
 import java.io.IOException;
+import java.util.concurrent.Callable;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * Instrumentation tests for VR Shell (Chrome VR)
@@ -177,4 +189,62 @@ public class VrShellTest extends ChromeTabbedActivityTestBase {
     public void testEnterExitVrModeUnsupportedImage() throws IOException {
         enterExitVrModeImage(false);
     }
+
+    /**
+     * Verify that resizing the CompositorViewHolder does not cause the current tab to resize while
+     * the CompositorViewHolder is detached from the TabModelSelector. See crbug.com/680240.
+     * @throws InterruptedException
+     * @throws TimeoutException
+     */
+    @SmallTest
+    @RetryOnFailure
+    public void testResizeWithCompositorViewHolderDetached()
+            throws InterruptedException, TimeoutException {
+        final AtomicReference<TabModelSelector> selector = new AtomicReference<>();
+        final AtomicReference<Integer> oldWidth = new AtomicReference<>();
+        final int testWidth = 123;
+        final ContentViewCore cvc = getActivity().getActivityTab().getActiveContentViewCore();
+
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                CompositorViewHolder compositorViewHolder = (CompositorViewHolder)
+                        getActivity().findViewById(R.id.compositor_view_holder);
+                selector.set(compositorViewHolder.detachForVR());
+                oldWidth.set(cvc.getViewportWidthPix());
+
+                ViewGroup.LayoutParams layoutParams = compositorViewHolder.getLayoutParams();
+                layoutParams.width = testWidth;
+                layoutParams.height = 456;
+                compositorViewHolder.requestLayout();
+            }
+        });
+        CriteriaHelper.pollUiThread(Criteria.equals(testWidth, new Callable<Integer>() {
+            @Override
+            public Integer call() {
+                return getActivity().findViewById(R.id.compositor_view_holder).getMeasuredWidth();
+            }
+        }));
+
+        assertEquals("Viewport width should not have changed when resizing a detached "
+                + "CompositorViewHolder",
+                cvc.getViewportWidthPix(),
+                oldWidth.get().intValue());
+
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                CompositorViewHolder compositorViewHolder = (CompositorViewHolder) getActivity()
+                        .findViewById(R.id.compositor_view_holder);
+                compositorViewHolder.onExitVR(selector.get());
+            }
+        });
+
+        CriteriaHelper.pollUiThread(Criteria.equals(testWidth, new Callable<Integer>() {
+            @Override
+            public Integer call() {
+                return cvc.getViewportWidthPix();
+            }
+        }));
+    }
 }