[TTS] Gather surrounding text on Tap before any UX.

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/action/SearchAction.java

Index: chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/action/SearchAction.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/action/SearchAction.java b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/action/SearchAction.java
new file mode 100644
index 0000000000000000000000000000000000000000..6a56863b34ffbace7be7c82eb65dbb5eeedad38f
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/action/SearchAction.java
@@ -0,0 +1,182 @@
+// Copyright 2016 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.action;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.chrome.browser.contextualsearch.gesture.SearchGestureHost;
+import org.chromium.content_public.browser.WebContents;
+
+/**
+ * Represents an abstract action to do a Contextual Search, and supports native C++ functionality.
+ * Subclasses will exist for a Resolved search action that determines the search based on page text,
+ * and Verbatim search action that just searches for the literal selection without providing
+ * context.
+ * This is part of the 2016-refactoring (crbug.com/624609, go/cs-refactoring-2016).
+ */
+public abstract class SearchAction {
+    private long mNativePointer;
+
+    protected final SearchActionListener mListener;
+    protected final SearchGestureHost mHost;
+
+    // ============================================================================================
+    // Constructor
+    // ============================================================================================
+
+    /**
+     * Constructs an action that knows how to Search.  Current implementation is limited to
+     * gathering the text on a Tap gesture in order to determine whether the Tap should be
+     * suppressed or a search should be done or not, implemented by the
+     * {@class ResolvedSearchAction} subclass.
+     * @param listener The object to notify when the {@link SearchAction} state changes.
+     * @param host The host object, which provides environment data.
+     */
+    public SearchAction(SearchActionListener listener, SearchGestureHost host) {
+        mHost = host;
+        mNativePointer = nativeInit();
+
+        mListener = listener;
+    }
+
+    // ============================================================================================
+    // Abstract
+    // ============================================================================================
+
+    /**
+     * Extracts the context for the current search -- text surrounding the location of the Tap
+     * gesture.
+     */
+    public abstract void extractContext();
+
+    // ============================================================================================
+    //
+    // ============================================================================================
+
+    /**
+     * Called when the system determines that this action will not be acted upon.
+     */
+    public void dismissAction() {
+        mHost.dismissGesture();
+    }
+
+    /**
+     * Should be called when this object is no longer needed to clean up storage.
+     */
+    public void destroyAction() {
+        onActionEnded();
+
+        if (mNativePointer != 0L) {
+            nativeDestroy(mNativePointer);
+        }
+    }
+
+    // ============================================================================================
+    // Suppression
+    // ============================================================================================
+
+    /**
+     * @return Whether this action should be suppressed.
+     */
+    protected boolean shouldSuppressAction() {
+        // TODO(donnd): integrate with native tap suppression.
+        return false;
+    }
+
+    // ============================================================================================
+    // State notification
+    // ============================================================================================
+
+    /**
+     * Sends notification that the context is ready for use now.
+     */
+    protected void notifyContextReady() {
+        onContextReady();
+    }
+
+    // ============================================================================================
+    // Surrounding Text
+    // ============================================================================================
+
+    /**
+     * Requests text surrounding the location of the caret.
+     */
+    protected void requestSurroundingText() {
+        WebContents webContents = mHost.getTabWebContents();
+        if (webContents != null) {
+            nativeRequestSurroundingText(mNativePointer, webContents);
+            // TODO(donnd): consider reusing this surrounding text for the resolve action too.
+            // Currently we make an additional request for the surroundings after the UX selects the
+            // word tapped, in order to resolve the search term based on that selection.
+        } else {
+            notifyContextReady();
+        }
+    }
+
+    @CalledByNative
+    protected void onSurroundingTextReady() {
+        // No base class action here, subclass may override and take action.
+    }
+
+    // ============================================================================================
+    // SearchAction states
+    // ============================================================================================
+
+    /**
+     * Called to notify that the current context is ready.
+     */
+    private void onContextReady() {
+        mListener.onContextReady(this);
+
+        if (shouldSuppressAction()) {
+            onActionSuppressed();
+        } else {
+            onActionAccepted();
+        }
+    }
+
+    /**
+     * Called when an action has been accepted to notify the listener.
+     */
+    private void onActionAccepted() {
+        mListener.onActionAccepted(this);
+    }
+
+    /**
+     * Called when an action has been suppressed to notify the listener.
+     */
+    private void onActionSuppressed() {
+        mListener.onActionSuppressed(this);
+
+        dismissAction();
+    }
+
+    /**
+     * Called when an action has ended to notify the listener.
+     */
+    private void onActionEnded() {
+        mListener.onActionEnded(this);
+    }
+
+    // ============================================================================================
+    // Internals
+    // ============================================================================================
+
+    @CalledByNative
+    private void clearNativePointer() {
+        assert mNativePointer != 0;
+        mNativePointer = 0;
+    }
+
+    // ============================================================================================
+    // Native methods.
+    // ============================================================================================
+
+    // Native calls.
+    private native long nativeInit();
+    private native void nativeDestroy(long nativeSearchAction);
+
+    private native void nativeRequestSurroundingText(
+            long nativeSearchAction, WebContents webContents);
+}