Implement SmartText selection.

content/public/android/java/src/org/chromium/content/browser/SelectionPopupController.java

Index: content/public/android/java/src/org/chromium/content/browser/SelectionPopupController.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/SelectionPopupController.java b/content/public/android/java/src/org/chromium/content/browser/SelectionPopupController.java
index c45ec5aca4667aeb45a3f0e9dd621e122ef2d4ee..0315d165df2091c14a1981f38bab97161f030b69 100644
--- a/content/public/android/java/src/org/chromium/content/browser/SelectionPopupController.java
+++ b/content/public/android/java/src/org/chromium/content/browser/SelectionPopupController.java
@@ -54,7 +54,7 @@ import java.util.List;
  */
 @TargetApi(Build.VERSION_CODES.M)
 public class SelectionPopupController extends ActionModeCallbackHelper {
-    private static final String TAG = "cr.SelectionPopCtlr";  // 20 char limit
+    private static final String TAG = "SelectionPopupCtlr"; // 20 char limit
 
     /**
      * Android Intent size limitations prevent sending over a megabyte of data. Limit
@@ -70,6 +70,12 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     // most such trailing, async delays.
     private static final int SHOW_DELAY_MS = 300;
 
+    // Display operation for ActionMode (show or invalidate) that is delayed because
+    // the selected text needs to be classified before. See comment to mPostponedDisplayOp.
+    private static final int POSTPONED_NONE = 0;
+    private static final int POSTPONED_SHOW = 1;
+    private static final int POSTPONED_INVALIDATE = 2;
+
     private final Context mContext;
     private final WindowAndroid mWindowAndroid;
     private final WebContents mWebContents;
@@ -115,6 +121,21 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     // The client that processes textual selection, or null if none exists.
     private SelectionClient mSelectionClient;
 
+    // The classificaton result of the selected text if the selection exists and
+    // ContextSelectionProvider was able to classify it, otherwise null.
+    private ContextSelectionProvider.Result mClassificationResult;
+
+    // Postponed display operation for ActionMode.
+    //
+    // The |mSelectionClient| might perform a recognition of the selected texts that
+    // can affect the ActionMode menu. In this case its method sendsPopupMenuUpdates()
+    // returns true and the client itself sends the results back asynchronously.
+    //
+    // With this kind of SelectionClient we postpone the display of ActionMode menu
+    // until the result comes, so we can update the menu before showing it and avoid the flicker.
+    // This variable holds the type of operation we have postponed, i.e. show or invalidate.
+    private int mPostponedDisplayOp = POSTPONED_NONE;

[boliu, 2017/03/22 02:32:12]

should mention this is only valid and not NONE if there's a pending request to
SelectionClient?

also, can do the IntDef stuff here too?

[Tima Vaisburd, 2017/03/24 22:13:55]

I followed Pedro's and your advises and tried to simplify my changes.
Now I only use showActionModeOrClearSelection() that always recreates the action
mode. With this instead of |mPostponedDisplayOp| I have a boolean flag.

Please take another look.

+
     /**
      * Create {@link SelectionPopupController} instance.
      * @param context Context for action mode.
@@ -145,6 +166,9 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
                 hideActionModeTemporarily(hideDuration);
             }
         };
+
+        mSelectionClient =
+                ContextSelectionClient.create(new ContextSelectionCallback(), window, webContents);
     }
 
     /**
@@ -189,15 +213,18 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
      *
      * <p>Action mode in floating mode is tried first, and then falls back to
      * a normal one.
-     * @return {@code true} if the action mode started successfully or is already on.
+     * <p> If the action mode cannot be created the selection is cleared.
      */
-    public boolean showActionMode() {
-        if (isEmpty()) return false;
+    public void showActionModeOrClearOnFailure() {
+        if (isEmpty()) {
+            clearSelection();
+            return;
+        }
 
         // Just refreshes the view if it is already showing.
         if (isActionModeValid()) {
             invalidateActionMode();
-            return true;
+            return;
         }
 
         if (mView.getParent() != null) {
@@ -213,7 +240,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
             mActionMode = actionMode;
         }
         mUnselectAllOnDismiss = true;
-        return isActionModeValid();
+        if (!isActionModeValid()) clearSelection();
     }
 
     @TargetApi(Build.VERSION_CODES.M)
@@ -295,6 +322,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
      */
     @Override
     public void finishActionMode() {
+        mPostponedDisplayOp = POSTPONED_NONE;

[boliu, 2017/03/22 02:32:12]

reset mClassificationResult here too?

[Tima Vaisburd, 2017/03/24 22:13:55]

I wanted to associate mClassificationResult with the selection, not the menu
(i.e. ActionMode). We need to reclassify when the selection appears or changes,
and the menu can be shown more often. I found one case where we should not reset
the result: ContentViewCore destroys and recreates ActionMode on rotation.

         if (isActionModeValid()) {
             mActionMode.finish();
 
@@ -314,6 +342,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
             assert canHideActionMode();
             mHidden = false;

[boliu, 2017/03/22 02:32:12]

so... 343-345 is a repeated at 392-394, factor out into a method that's maybe
called "unhideActionMode" or something like that? And this SHOW_DELAY_MS thing
deserves a comment here

[Tima Vaisburd, 2017/03/24 22:13:55]

This code changed. Since I do not try to invalidate any more I do not need to
unhide it too places.

             mView.removeCallbacks(mRepeatingHideRunnable);
+            hideActionModeTemporarily(SHOW_DELAY_MS);
             mPendingInvalidateContentRect = false;
         }
 
@@ -328,7 +357,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     /**
      * @see ActionMode#invalidateContentRect()
      */
-    public void invalidateContentRect() {
+    private void invalidateContentRect() {
         if (supportsFloatingActionMode()) {
             if (mHidden) {
                 mPendingInvalidateContentRect = true;
@@ -431,6 +460,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     private void createActionMenu(ActionMode mode, Menu menu) {
         mNeedsPrepare = false;
         initializeMenu(mContext, mode, menu);
+        updateContextDependentMenuItem(menu);
 
         if (!isSelectionEditable() || !canPaste()) {
             menu.removeItem(R.id.select_action_menu_paste);
@@ -473,6 +503,20 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         return clipMgr.hasPrimaryClip();
     }
 
+    private void updateContextDependentMenuItem(Menu menu) {
+        MenuItem assistItem = menu.findItem(R.id.select_action_menu_context_dep);
+        if (assistItem == null) return;
+
+        if (mClassificationResult == null) {
+            assistItem.setVisible(false).setEnabled(false);
+        } else {
+            assistItem.setVisible(true)
+                    .setEnabled(true)
+                    .setTitle(mClassificationResult.label)
+                    .setIcon(mClassificationResult.icon);
+        }
+    }
+
     /**
      * Intialize the menu items for processing text, if there is any.
      */
@@ -488,7 +532,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         for (int i = 0; i < supportedActivities.size(); i++) {
             ResolveInfo resolveInfo = supportedActivities.get(i);
             CharSequence label = resolveInfo.loadLabel(mContext.getPackageManager());
-            menu.add(R.id.select_action_menu_text_processing_menus, Menu.NONE, i, label)
+            menu.add(R.id.select_action_menu_text_processing_menus, Menu.NONE, Menu.NONE, label)
                     .setIntent(createProcessTextIntentForResolveInfo(resolveInfo))
                     .setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
         }
@@ -514,7 +558,10 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         int id = item.getItemId();
         int groupId = item.getGroupId();
 
-        if (id == R.id.select_action_menu_select_all) {
+        if (id == R.id.select_action_menu_context_dep) {
+            doContextDependentAction();
+            mode.finish();
+        } else if (id == R.id.select_action_menu_select_all) {
             selectAll();
         } else if (id == R.id.select_action_menu_cut) {
             cut();
@@ -573,6 +620,30 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     }
 
     /**
+     * Perform an action that depends on the semantics of the selected text.
+     */
+    @VisibleForTesting
+    void doContextDependentAction() {
+        if (mClassificationResult == null) return;
+
+        assert mClassificationResult.onClickListener != null
+                || mClassificationResult.intent != null;
+
+        if (mClassificationResult.onClickListener != null) {
+            mClassificationResult.onClickListener.onClick(mView);
+            return;
+        }
+
+        if (mClassificationResult.intent != null) {
+            Context context = mWindowAndroid.getContext().get();
+            if (context == null) return;
+
+            context.startActivity(mClassificationResult.intent);
+            return;
+        }
+    }
+
+    /**
      * Perform a select all action.
      */
     @VisibleForTesting
@@ -750,7 +821,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
 
     void restoreSelectionPopupsIfNecessary() {
         if (mHasSelection && !isActionModeValid()) {
-            if (!showActionMode()) clearSelection();
+            showActionModeOrClearOnFailure();
         }
     }
 
@@ -767,7 +838,11 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
                 mSelectionRect.set(left, top, right, bottom);
                 mHasSelection = true;
                 mUnselectAllOnDismiss = true;
-                if (!showActionMode()) clearSelection();
+                if (mSelectionClient != null && mSelectionClient.sendsSelectionPopupUpdates()) {
+                    mPostponedDisplayOp = POSTPONED_SHOW;
+                } else {
+                    showActionModeOrClearOnFailure();
+                }
                 break;
 
             case SelectionEventType.SELECTION_HANDLES_MOVED:
@@ -787,7 +862,11 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
                 break;
 
             case SelectionEventType.SELECTION_HANDLE_DRAG_STOPPED:
-                hideActionMode(false);
+                if (mSelectionClient != null && mSelectionClient.sendsSelectionPopupUpdates()) {
+                    mPostponedDisplayOp = POSTPONED_INVALIDATE;
+                } else {
+                    hideActionMode(false);
+                }
                 break;
 
             case SelectionEventType.INSERTION_HANDLE_SHOWN:
@@ -848,6 +927,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
      * end if applicable.
      */
     void clearSelection() {
+        mClassificationResult = null;
         if (mWebContents == null || isEmpty()) return;
         mWebContents.collapseSelection();
     }
@@ -916,4 +996,53 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         return mContext.getPackageManager().queryIntentActivities(intent,
                 PackageManager.MATCH_DEFAULT_ONLY).size() > 0;
     }
+
+    // The callback class that delivers result from a ContextSelectionClient.
+    private class ContextSelectionCallback implements ContextSelectionProvider.ResultCallback {
+        @Override
+        public void onClassified(ContextSelectionProvider.Result result) {
+            // If the selection does not exist any more, discard |result|.
+            if (!mHasSelection) {
+                mPostponedDisplayOp = POSTPONED_NONE;
+                return;
+            }
+
+            // Update the selection range if needed.
+            if (!(result.startAdjust == 0 && result.endAdjust == 0)) {
+                // This call causes SELECTION_HANDLES_MOVED event
+                mWebContents.adjustSelectionByCharacterOffset(result.startAdjust, result.endAdjust);
+            }
+
+            final boolean hadPriorResult = mClassificationResult != null;
+            mClassificationResult = result.hasNamedAction() ? result : null;
+
+            // For simplicity always update the menu if we need to show assist item.
+            // Also we need to update the menu if the assist item is going to disappear.
+            if (mClassificationResult != null || hadPriorResult) mNeedsPrepare = true;
+
+            switch (mPostponedDisplayOp) {
+                case POSTPONED_NONE:
+                    break;
+
+                case POSTPONED_SHOW:
+                    // TODO(timav): if the |result| contained the selection adjustment and
+                    // we called adjustSelectionByCharacterOffset() above, there is a
+                    // flicker if SELECTION_HANDLES_MOVED comes later and invalidates the
+                    // selection rectangle. Consider postponing till SELECTION_HANDLES_MOVED
+                    // or introduce delay.
+                    showActionModeOrClearOnFailure();
+                    mPostponedDisplayOp = POSTPONED_NONE;
+                    break;
+
+                case POSTPONED_INVALIDATE:
+                    invalidateActionMode();
+                    mPostponedDisplayOp = POSTPONED_NONE;
+                    break;
+
+                default:
+                    assert false : "Invalid postponed display operation type.";
+                    break;
+            }
+        }
+    };
 }