Make ViewRoot the top of the ViewAndroid tree

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

Index: chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
index 2f573f6189295b7ac05c85ae2d4a2a1fbea1ffff..23975fa627135516c4512f03d666c1899273fd39 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
@@ -106,6 +106,7 @@ import org.chromium.printing.PrintingController;
 import org.chromium.printing.PrintingControllerImpl;
 import org.chromium.ui.base.LocalizationUtils;
 import org.chromium.ui.base.PageTransition;
+import org.chromium.ui.base.ViewRoot;
 import org.chromium.ui.base.WindowAndroid;
 import org.chromium.ui.mojom.WindowOpenDisposition;
 
@@ -162,6 +163,9 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
      */
     private final Context mThemedApplicationContext;
 
+    /** {@link ViewRoot} used to forward input/view events down to native. */
+    private ViewRoot mViewRoot;
+
     /** Gives {@link Tab} a way to interact with the Android window. */
     private WindowAndroid mWindowAndroid;
 
@@ -474,10 +478,10 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
      *
      * @param id        The id this tab should be identified with.
      * @param incognito Whether or not this tab is incognito.
-     * @param window    An instance of a {@link WindowAndroid}.
+     * @param viewRoot  An instance of a {@link ViewRoot}.
      */
-    public Tab(int id, boolean incognito, WindowAndroid window) {
-        this(id, INVALID_TAB_ID, incognito, null, window, null, null, null);
+    public Tab(int id, boolean incognito, ViewRoot viewRoot) {
+        this(id, INVALID_TAB_ID, incognito, null, viewRoot, null, null, null);
     }
 
     /**
@@ -490,21 +494,21 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
      * @param parentId    The id id of the tab that caused this tab to be opened.
      * @param incognito   Whether or not this tab is incognito.
      * @param context     An instance of a {@link Context}.
-     * @param window      An instance of a {@link WindowAndroid}.
+     * @param viewRoot    An instance of a {@link ViewRoot}.
      * @param creationState State in which the tab is created, needed to initialize TabUma
      *                      accounting. When null, TabUma will not be initialized.
      * @param frozenState State containing information about this Tab, if it was persisted.
      */
     @SuppressLint("HandlerLeak")
-    public Tab(int id, int parentId, boolean incognito, Context context,
-            WindowAndroid window, TabLaunchType type, TabCreationState creationState,
-            TabState frozenState) {
+    public Tab(int id, int parentId, boolean incognito, Context context, ViewRoot viewRoot,
+            TabLaunchType type, TabCreationState creationState, TabState frozenState) {
         mId = TabIdManager.getInstance().generateValidId(id);
         mParentId = parentId;
         mIncognito = incognito;
         mThemedApplicationContext = context != null ? new ContextThemeWrapper(
                 context.getApplicationContext(), ChromeActivity.getThemeId()) : null;
-        mWindowAndroid = window;
+        mViewRoot = viewRoot;
+        mWindowAndroid = viewRoot != null ? viewRoot.getWindowAndroid() : null;
         mLaunchType = type;
         if (mThemedApplicationContext != null) {
             Resources resources = mThemedApplicationContext.getResources();
@@ -1400,7 +1404,7 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
             // TODO(yusufo): We can't call updateWindowAndroid here and set mWindowAndroid to null
             // because many code paths (including navigation) expect the tab to always be associated
             // with an activity, and will crash. crbug.com/657007
-            if (mContentViewCore != null) mContentViewCore.updateWindowAndroid(null);
+            if (mContentViewCore != null) mContentViewCore.updateViewRoot(null);
             attachTabContentManager(null);
         }
 
@@ -1422,7 +1426,7 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
         // TODO(yusufo): Share these calls with the construction related calls.
         // crbug.com/590281
 
-        updateWindowAndroid(activity.getWindowAndroid());
+        updateViewRoot(activity.getViewRoot());
 
         // Update for the controllers that need the Compositor from the new Activity.
         attachTabContentManager(activity.getTabContentManager());
@@ -1454,14 +1458,15 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
     }
 
     /**
-     * Update and propagate the new WindowAndroid.
-     * @param windowAndroid The WindowAndroid to propagate.
+     * Update and propagate the new ViewRoot and the accompanying WindowAndroid.
+     * @param viewRoot The viewRoot to update.
      */
-    public void updateWindowAndroid(WindowAndroid windowAndroid) {
+    public void updateViewRoot(ViewRoot viewRoot) {
         // TODO(yusufo): mWindowAndroid can never be null until crbug.com/657007 is fixed.
-        assert windowAndroid != null;
-        mWindowAndroid = windowAndroid;
-        if (mContentViewCore != null) mContentViewCore.updateWindowAndroid(mWindowAndroid);
+        assert viewRoot.getWindowAndroid() != null;
+        mViewRoot = viewRoot;
+        mWindowAndroid = viewRoot.getWindowAndroid();
+        if (mContentViewCore != null) mContentViewCore.updateViewRoot(viewRoot);
     }
 
     /**
@@ -1500,6 +1505,13 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
     }
 
     /**
+     * @return @{@link ViewRoot} instance used to forward view/input events.
+     */
+    public ViewRoot getViewRoot() {
+        return mViewRoot;
+    }
+
+    /**
      * Called when a navigation begins and no navigation was in progress
      * @param toDifferentDocument Whether this navigation will transition between
      * documents (i.e., not a fragment navigation or JS History API call).
@@ -1594,8 +1606,7 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
         ContentView cv = ContentView.createContentView(mThemedApplicationContext, cvc);
         cv.setContentDescription(mThemedApplicationContext.getResources().getString(
                 R.string.accessibility_content_view));
-        cvc.initialize(new TabViewAndroidDelegate(this, cv), cv, webContents,
-                getWindowAndroid());
+        cvc.initialize(new TabViewAndroidDelegate(this, cv), cv, webContents, mViewRoot);
         ChromeActionModeCallback actionModeCallback = new ChromeActionModeCallback(
                 mThemedApplicationContext, this, cvc.getActionModeCallbackHelper());
         cvc.setActionModeCallback(actionModeCallback);
@@ -2845,12 +2856,11 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
      * on cold start that should be loaded when switched to. initialize() needs to be called
      * afterwards to complete the second level initialization.
      */
-    public static Tab createFrozenTabFromState(
-            int id, ChromeActivity activity, boolean incognito,
-            WindowAndroid nativeWindow, int parentId, TabState state) {
+    public static Tab createFrozenTabFromState(int id, ChromeActivity activity, boolean incognito,
+            ViewRoot viewRoot, int parentId, TabState state) {
         assert state != null;
-        return new Tab(id, parentId, incognito, activity, nativeWindow,
-                TabLaunchType.FROM_RESTORE, TabCreationState.FROZEN_ON_RESTORE, state);
+        return new Tab(id, parentId, incognito, activity, viewRoot, TabLaunchType.FROM_RESTORE,
+                TabCreationState.FROZEN_ON_RESTORE, state);
     }
 
     /**
@@ -2890,10 +2900,8 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
      * complete the second level initialization.
      */
     public static Tab createTabForLazyLoad(ChromeActivity activity, boolean incognito,
-            WindowAndroid nativeWindow, TabLaunchType type, int parentId,
-            LoadUrlParams loadUrlParams) {
-        Tab tab = new Tab(
-                INVALID_TAB_ID, parentId, incognito, activity, nativeWindow, type,
+            ViewRoot viewRoot, TabLaunchType type, int parentId, LoadUrlParams loadUrlParams) {
+        Tab tab = new Tab(INVALID_TAB_ID, parentId, incognito, activity, viewRoot, type,
                 TabCreationState.FROZEN_FOR_LAZY_LOAD, null);
         tab.setPendingLoadParams(loadUrlParams);
         return tab;
@@ -2905,10 +2913,11 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
      * @param initiallyHidden true iff the tab being created is initially in background
      */
     public static Tab createLiveTab(int id, ChromeActivity activity, boolean incognito,
-            WindowAndroid nativeWindow, TabLaunchType type, int parentId, boolean initiallyHidden) {
-        return new Tab(id, parentId, incognito, activity, nativeWindow, type, initiallyHidden
-                ? TabCreationState.LIVE_IN_BACKGROUND
-                : TabCreationState.LIVE_IN_FOREGROUND, null);
+            ViewRoot viewRoot, TabLaunchType type, int parentId, boolean initiallyHidden) {
+        return new Tab(id, parentId, incognito, activity, viewRoot, type,
+                initiallyHidden ? TabCreationState.LIVE_IN_BACKGROUND
+                                : TabCreationState.LIVE_IN_FOREGROUND,
+                null);
     }
 
     /**