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..e6cb5c873c06b1995e6909a34ffd3923f7f8dfe0 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 +121,67 @@ 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 or null if ContextSelectionProvider
+    // could not classify the selection.

[boliu, 2017/03/20 20:27:26]

what's the state of this if there's no selection?

[Tima Vaisburd, 2017/03/21 02:07:02]

Null. I rewrote as
"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.
+    // TODO(timav): explain better.

[boliu, 2017/03/20 20:27:26]

later when?

[Tima Vaisburd, 2017/03/21 02:07:02]

Added an explanation.

+    private int mPostponedDisplayOp;
+
+    // The callback object that delivers result from SelectionClient.
+    private ContextSelectionProvider.ResultCallback mSelectonCallback =

[amaralp, 2017/03/21 02:34:14]

Why does this need to be a member of the class? Why not instantiate it directly
when calling ContextSelectionClient.create()?

[Tima Vaisburd, 2017/03/21 20:50:12]

No good reason.
Added a private class ContextSelectionCallback and did just that.

+            new ContextSelectionProvider.ResultCallback() {
+                @Override
+                public void onClassified(ContextSelectionProvider.Result result) {
+                    Log.v(TAG, "onClassified");

[boliu, 2017/03/20 20:27:26]

.

[Tima Vaisburd, 2017/03/21 02:07:02]

No more.

+
+                    // 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

[amaralp, 2017/03/21 02:34:14]

One solution for the flickering could be to have the original (un-extended)
selection never appear. Instead of triggering the ContextSelectionClient on
|SELECTION_HANDLE_SHOWN| you could do it in Blink before the selection is made
and prevent the intermediate selection. What I'm thinking is that whenever a
touch selection occurs in Blink it could send an IPC to the browser with the
selected text and context. The browser figures out what more to select and sends
an IPC back to Blink.
This would also have the added benefit of not having to postpone the action
mode.

[Tima Vaisburd, 2017/03/21 20:50:12]

I like that idea although I receive a feedback that the next feature requirement
could be an animation of the selection expansion.

I thought, however, that for the IPC I either have to use the existing one or
change both this and contextual search to use the same mechanism. I wanted to
avoid the latter. Can we have this kind of improvement in later CLs?
 
I think I still need to postpone invalidate() after user stops the drag?

+                            // we called adjustSelectionByCharacterOffset() above, there is flicker
+                            // if SELECTION_HANDLES_MOVED comes later and invalidates selection
+                            // rectangle. Consider postponing till SELECTION_HANDLES_MOVED or
+                            // introduce delay.
+                            showActionMode();
+                            mPostponedDisplayOp = POSTPONED_NONE;
+                            break;
+
+                        case POSTPONED_INVALIDATE:
+                            invalidateActionMode();
+                            mPostponedDisplayOp = POSTPONED_NONE;
+                            break;
+
+                        default:
+                            assert false : "Invalid postponed display operation type.";
+                            break;
+                    }
+                }
+            };
+
     /**
      * Create {@link SelectionPopupController} instance.
      * @param context Context for action mode.
@@ -145,6 +212,8 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
                 hideActionModeTemporarily(hideDuration);
             }
         };
+
+        mSelectionClient = ContextSelectionClient.create(mSelectonCallback, window, webContents);
     }
 
     /**
@@ -189,15 +258,18 @@ 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 showActionMode() {

[boliu, 2017/03/20 20:27:26]

maybe call this showActionModeOrClearOnFailure

[Ted C, 2017/03/20 20:35:50]

Ah, that is why the other code changed.

[Tima Vaisburd, 2017/03/21 02:07:02]

Done.

+        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 +285,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
             mActionMode = actionMode;
         }
         mUnselectAllOnDismiss = true;
-        return isActionModeValid();
+        if (!isActionModeValid()) clearSelection();
     }
 
     @TargetApi(Build.VERSION_CODES.M)
@@ -295,6 +367,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
      */
     @Override
     public void finishActionMode() {
+        mPostponedDisplayOp = POSTPONED_NONE;
         if (isActionModeValid()) {
             mActionMode.finish();
 
@@ -314,6 +387,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
             assert canHideActionMode();
             mHidden = false;
             mView.removeCallbacks(mRepeatingHideRunnable);
+            hideActionModeTemporarily(SHOW_DELAY_MS);
             mPendingInvalidateContentRect = false;
         }
 
@@ -328,7 +402,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     /**
      * @see ActionMode#invalidateContentRect()
      */
-    public void invalidateContentRect() {
+    private void invalidateContentRect() {
         if (supportsFloatingActionMode()) {
             if (mHidden) {
                 mPendingInvalidateContentRect = true;
@@ -431,6 +505,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     private void createActionMenu(ActionMode mode, Menu menu) {
         mNeedsPrepare = false;
         initializeMenu(mContext, mode, menu);
+        updateContextDependantMenuItem(menu);
 
         if (!isSelectionEditable() || !canPaste()) {
             menu.removeItem(R.id.select_action_menu_paste);
@@ -473,6 +548,18 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         return clipMgr.hasPrimaryClip();
     }
 
+    private void updateContextDependantMenuItem(Menu menu) {
+        Log.v(TAG, "updateContextDependantItem");

[boliu, 2017/03/20 20:27:26]

.

[Tima Vaisburd, 2017/03/21 02:07:02]

Removed. Also s/dependant/dependent/.

+        menu.removeItem(R.id.select_action_menu_context_dep);
+
+        if (mClassificationResult == null) return;
+
+        Log.v(TAG, "updateContextDependantMenuItem: adding item " + mClassificationResult.label);
+        menu.add(Menu.NONE, R.id.select_action_menu_context_dep, 1, mClassificationResult.label)
+                .setIcon(mClassificationResult.icon)
+                .setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
+    }
+
     /**
      * Intialize the menu items for processing text, if there is any.
      */
@@ -514,7 +601,10 @@ 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 +663,30 @@ 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 +864,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
 
     void restoreSelectionPopupsIfNecessary() {
         if (mHasSelection && !isActionModeValid()) {
-            if (!showActionMode()) clearSelection();
+            showActionMode();
         }
     }
 
@@ -767,7 +881,11 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
                 mSelectionRect.set(left, top, right, bottom);
                 mHasSelection = true;
                 mUnselectAllOnDismiss = true;
-                if (!showActionMode()) clearSelection();
+                if (mSelectionClient != null && mSelectionClient.sendsMenuUpdates()) {
+                    mPostponedDisplayOp = POSTPONED_SHOW;
+                } else {
+                    showActionMode();
+                }
                 break;
 
             case SelectionEventType.SELECTION_HANDLES_MOVED:
@@ -787,7 +905,11 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
                 break;
 
             case SelectionEventType.SELECTION_HANDLE_DRAG_STOPPED:
-                hideActionMode(false);
+                if (mSelectionClient != null && mSelectionClient.sendsMenuUpdates()) {
+                    mPostponedDisplayOp = POSTPONED_INVALIDATE;
+                } else {
+                    hideActionMode(false);
+                }
                 break;
 
             case SelectionEventType.INSERTION_HANDLE_SHOWN:
@@ -848,6 +970,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
      * end if applicable.
      */
     void clearSelection() {
+        mClassificationResult = null;
         if (mWebContents == null || isEmpty()) return;
         mWebContents.collapseSelection();
     }