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 679523249b08b25c8a1cf50a9441352dc7952ea9..be44f4cb55c484a657c3f8ca3ba0358c7a5a4f96 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
@@ -115,6 +115,16 @@ 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;
+
+    // The resource ID for Assist menu item.
+    private int mAssistMenuItemId;
+
+    // This variable is set to true when the classification request is in progress.
+    private boolean mPendingClassificationRequest;
+
     /**
      * Create {@link SelectionPopupController} instance.
      * @param context Context for action mode.
@@ -145,6 +155,13 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
                 hideActionModeTemporarily(hideDuration);
             }
         };
+
+        mSelectionClient =
+                ContextSelectionClient.create(new ContextSelectionCallback(), window, webContents);
+
+        // TODO(timav): Use android.R.id.textAssist for the Assist item id once we switch to
+        // Android O SDK and remove |mAssistMenuItemId|.
+        mAssistMenuItemId = mContext.getResources().getIdentifier("textAssist", "id", "android");
     }
 
     /**
@@ -174,9 +191,9 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         return mActionMode != null;
     }
 
-    // True if action mode is not yet initialized or set to no-op mode.
-    private boolean isEmpty() {
-        return mCallback == EMPTY_CALLBACK;
+    // True if action mode is initialized to a working (not a no-op) mode.
+    private boolean isActionModeSupported() {
+        return mCallback != EMPTY_CALLBACK;
     }
 
     @Override
@@ -189,15 +206,19 @@ 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 (!isActionModeSupported()) return;
 
-        destroyActionModeAndKeepSelection();
+        // Just refresh the view if action mode already exists.
+        if (isActionModeValid()) {
+            invalidateActionMode();
+            return;
+        }
 
         if (mView.getParent() != null) {
-             // On ICS, startActionMode throws an NPE when getParent() is null.
+            // On ICS, startActionMode throws an NPE when getParent() is null.
             assert mWebContents != null;
             ActionMode actionMode = supportsFloatingActionMode()
                     ? startFloatingActionMode()
@@ -209,7 +230,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
             mActionMode = actionMode;
         }
         mUnselectAllOnDismiss = true;
-        return isActionModeValid();
+        if (!isActionModeValid()) clearSelection();
     }
 
     @TargetApi(Build.VERSION_CODES.M)
@@ -284,6 +305,10 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
      */
     @Override
     public void finishActionMode() {
+        mPendingClassificationRequest = false;
+        mHidden = false;
+        mView.removeCallbacks(mRepeatingHideRunnable);
+
         if (isActionModeValid()) {
             mActionMode.finish();
 
@@ -293,9 +318,31 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     }
 
     /**
+     * @see ActionMode#invalidate()
+     * Note that invalidation will also reset visibility state. The caller
+     * should account for this when making subsequent visibility updates.
+     */
+    private void invalidateActionMode() {
+        if (!isActionModeValid()) return;
+        if (mHidden) {
+            assert canHideActionMode();
+            mHidden = false;
+            unhideActionMode();
+            mPendingInvalidateContentRect = false;
+        }
+
+        // Try/catch necessary for framework bug, crbug.com/446717.
+        try {
+            mActionMode.invalidate();
+        } catch (NullPointerException e) {
+            Log.w(TAG, "Ignoring NPE from ActionMode.invalidate() as workaround for L", e);
+        }
+    }
+
+    /**
      * @see ActionMode#invalidateContentRect()
      */
-    public void invalidateContentRect() {
+    private void invalidateContentRect() {
         if (supportsFloatingActionMode()) {
             if (mHidden) {
                 mPendingInvalidateContentRect = true;
@@ -328,8 +375,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
             mRepeatingHideRunnable.run();
         } else {
             mHidden = false;
-            mView.removeCallbacks(mRepeatingHideRunnable);
-            hideActionModeTemporarily(SHOW_DELAY_MS);
+            unhideActionMode();
             if (mPendingInvalidateContentRect) {
                 mPendingInvalidateContentRect = false;
                 invalidateContentRect();
@@ -337,6 +383,12 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         }
     }
 
+    private void unhideActionMode() {
+        mView.removeCallbacks(mRepeatingHideRunnable);
+        // To show the action mode that is being hidden call hide() again with a short delay.
+        hideActionModeTemporarily(SHOW_DELAY_MS);
+    }
+
     /**
      * @see ActionMode#hide(long)
      */
@@ -398,6 +450,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     private void createActionMenu(ActionMode mode, Menu menu) {
         mNeedsPrepare = false;
         initializeMenu(mContext, mode, menu);
+        updateAssistMenuItem(menu);
 
         if (!isSelectionEditable() || !canPaste()) {
             menu.removeItem(R.id.select_action_menu_paste);
@@ -440,6 +493,21 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         return clipMgr.hasPrimaryClip();
     }
 
+    private void updateAssistMenuItem(Menu menu) {
+        // The assist menu item ID has to be equal to android.R.id.textAssist. Until we compile
+        // with Android O SDK where this ID is defined we replace the corresponding inflated
+        // item with an item with the proper ID.
+        // TODO(timav): Use android.R.id.textAssist for the Assist item id once we switch to
+        // Android O SDK and remove |mAssistMenuItemId|.
+        menu.removeItem(R.id.select_action_menu_assist);
+        if (mAssistMenuItemId == 0) return;
+
+        if (mClassificationResult != null && mClassificationResult.hasNamedAction()) {
+            menu.add(mAssistMenuItemId, mAssistMenuItemId, 1, mClassificationResult.label)
+                    .setIcon(mClassificationResult.icon);
+        }
+    }
+
     /**
      * Intialize the menu items for processing text, if there is any.
      */
@@ -452,10 +520,12 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         PackageManager packageManager = mContext.getPackageManager();
         List<ResolveInfo> supportedActivities =
                 packageManager.queryIntentActivities(createProcessTextIntent(), 0);
+        // Force text processing menu at the end.
+        final int order = 100;
         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, order + i, label)
                     .setIntent(createProcessTextIntentForResolveInfo(resolveInfo))
                     .setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
         }
@@ -481,7 +551,10 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
         int id = item.getItemId();
         int groupId = item.getGroupId();
 
-        if (id == R.id.select_action_menu_select_all) {
+        if (id == mAssistMenuItemId) {
+            doAssistAction();
+            mode.finish();
+        } else if (id == R.id.select_action_menu_select_all) {
             selectAll();
         } else if (id == R.id.select_action_menu_cut) {
             cut();
@@ -540,11 +613,38 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     }
 
     /**
+     * Perform an action that depends on the semantics of the selected text.
+     */
+    @VisibleForTesting
+    void doAssistAction() {
+        if (mClassificationResult == null || !mClassificationResult.hasNamedAction()) 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
     void selectAll() {
         mWebContents.selectAll();
+        mClassificationResult = null;
+        mNeedsPrepare = true;
+        invalidateActionMode();
         // Even though the above statement logged a SelectAll user action, we want to
         // track whether the focus was in an editable field, so log that too.
         if (isSelectionEditable()) {
@@ -717,7 +817,7 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
 
     void restoreSelectionPopupsIfNecessary() {
         if (mHasSelection && !isActionModeValid()) {
-            if (!showActionMode()) clearSelection();
+            showActionModeOrClearOnFailure();
         }
     }
 
@@ -734,7 +834,13 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
                 mSelectionRect.set(left, top, right, bottom);
                 mHasSelection = true;
                 mUnselectAllOnDismiss = true;
-                if (!showActionMode()) clearSelection();
+                if (mSelectionClient != null && mSelectionClient.sendsSelectionPopupUpdates()) {
+                    // Rely on |mSelectionClient| sending a classification request and the request
+                    // always calling onClassified() callback.
+                    mPendingClassificationRequest = true;
+                } else {
+                    showActionModeOrClearOnFailure();
+                }
                 break;
 
             case SelectionEventType.SELECTION_HANDLES_MOVED:
@@ -754,7 +860,13 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
                 break;
 
             case SelectionEventType.SELECTION_HANDLE_DRAG_STOPPED:
-                hideActionMode(false);
+                if (mSelectionClient != null && mSelectionClient.sendsSelectionPopupUpdates()) {
+                    // Rely on |mSelectionClient| sending a classification request and the request
+                    // always calling onClassified() callback.
+                    mPendingClassificationRequest = true;
+                } else {
+                    hideActionMode(false);
+                }
                 break;
 
             case SelectionEventType.INSERTION_HANDLE_SHOWN:
@@ -815,8 +927,9 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
      * end if applicable.
      */
     void clearSelection() {
-        if (mWebContents == null || isEmpty()) return;
+        if (mWebContents == null || !isActionModeSupported()) return;
         mWebContents.collapseSelection();
+        mClassificationResult = null;
     }
 
     void onSelectionChanged(String text) {
@@ -829,6 +942,11 @@ public class SelectionPopupController extends ActionModeCallbackHelper {
     // The client that implements selection augmenting functionality, or null if none exists.
     void setSelectionClient(SelectionClient selectionClient) {
         mSelectionClient = selectionClient;
+
+        mClassificationResult = null;
+
+        assert !mPendingClassificationRequest;
+        assert !mHidden;
     }
 
     void onShowUnhandledTapUIIfNeeded(int x, int y) {
@@ -883,4 +1001,47 @@ 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) {
+            boolean pendingClassificationRequest = mPendingClassificationRequest;
+            mPendingClassificationRequest = false;
+
+            // If the selection does not exist any more, discard |result|.
+            if (!mHasSelection) {
+                assert !mHidden;
+                assert mClassificationResult == null;
+                return;
+            }
+
+            // Determine whether we need to recreate the menu in case we are doing invalidate().
+            final boolean hadOldResult =
+                    mClassificationResult != null && mClassificationResult.hasNamedAction();
+            final boolean hasNewResult = result != null && result.hasNamedAction();
+
+            mClassificationResult = result;
+
+            // By the time this methos arrives the action mode might be finished or finished
+            // and recreated again. In both cases |pendingClassificationRequest == false|.
+            // Assume that if acton mode exists we need to invalidate in any case.
+            if (!pendingClassificationRequest && !isActionModeValid()) {
+                assert !mHidden;
+                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);
+            }
+
+            // For simplicity always recreate the menu if the new result exists.
+            mNeedsPrepare = hasNewResult || hadOldResult;
+
+            // Rely on this method to clear mHidden and unhide the action mode.
+            showActionModeOrClearOnFailure();
+        }
+    };
 }