Adds selection expansion support for Contextual Search.

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchSelectionController.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.contextualsearch;
 
 import android.os.Handler;
 
 import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.browser.ChromeActivity;
@@ skipping 37 matching lines @@
     private final float mPxToDp;
     private final Pattern mContainsWordPattern;
 
     private String mSelectedText;
     private SelectionType mSelectionType;
     private boolean mWasTapGestureDetected;
     private boolean mIsSelectionBeingModified;
     private boolean mWasLastTapValid;
     private boolean mIsWaitingForInvalidTapDetection;
     private boolean mShouldHandleSelectionModification;
+    private boolean mDidExpandSelection;
 
     private float mX;
     private float mY;
 
     private class ContextualSearchGestureStateListener extends GestureStateListener {
         @Override
         public void onScrollStarted(int scrollOffsetY, int scrollExtentY) {
             mHandler.handleScroll();
         }
 
@@ skipping 74 matching lines @@
             baseContentView.clearSelection();
         }
         resetAllStates();
     }
 
     /**
      * Handles a change in the current Selection.
      * @param selection The selection portion of the context.
      */
     void handleSelectionChanged(String selection) {
+        if (mDidExpandSelection) {
+            mDidExpandSelection = false;
+            return;
+        }
+
         if (selection == null || selection.isEmpty()) {
             scheduleInvalidTapNotification();
             // When the user taps on the page it will place the caret in that position, which
             // will trigger a onSelectionChanged event with an empty string.
             if (mSelectionType == SelectionType.TAP) {
                 // Since we mostly ignore a selection that's empty, we only need to partially reset.
                 resetSelectionStates();
                 return;
             }
         }
@@ skipping 112 matching lines @@
 
     /**
      * @return The Base Page's {@link ContentViewCore}, or {@code null} if there is no current tab.
      */
     ContentViewCore getBaseContentView() {
         Tab currentTab = mActivity.getActivityTab();
         return currentTab != null ? currentTab.getContentViewCore() : null;
     }
 
     /**
+     * Expands the current selection by the specified amounts.
+     * @param selectionStartAdjust The start offset adjustment of the selection to use to highlight
+     *                             the search term.
+     * @param selectionEndAdjust The end offset adjustment of the selection to use to highlight
+     *                           the search term.
+     */
+    void adjustSelection(int selectionStartAdjust, int selectionEndAdjust) {
+        // TODO(donnd): add code to verify that the selection is still valid before changing it.
+        // crbug.com/508354
+
+        if (selectionStartAdjust == 0 && selectionEndAdjust == 0) return;
+        ContentViewCore basePageContentView = getBaseContentView();
+        if (basePageContentView != null && basePageContentView.getWebContents() != null) {
+            mDidExpandSelection = true;
+            basePageContentView.getWebContents().adjustSelectionByCharacterOffset(
+                    selectionStartAdjust, selectionEndAdjust);
+        }
+    }
+
+    /**
      * @return whether a tap at the given coordinates should be handled or not.
      */
     private boolean shouldHandleTap(int x, int y) {
         return !mWasLastTapValid || wasTapCloseToPreviousTap(x, y);
     }
 
     /**
      * Determines whether a tap at the given coordinates is considered "close" to the previous
      * tap.
      */
@@ skipping 60 matching lines @@
     /**
      * Determines if the given selection contains a word or not.
      * @param selection The the selection to check for a word.
      * @return Whether the selection contains a word anywhere within it or not.
      */
     @VisibleForTesting
     public boolean doesContainAWord(String selection) {
         return mContainsWordPattern.matcher(selection).find();
     }
 }