Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchTabHelper.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 org.chromium.base.CalledByNative;
+import org.chromium.chrome.browser.CompositorChromeActivity;
+import org.chromium.chrome.browser.EmptyTabObserver;
+import org.chromium.chrome.browser.Tab;
+import org.chromium.chrome.browser.preferences.PrefServiceBridge;
+import org.chromium.chrome.browser.profiles.Profile;
+import org.chromium.chrome.browser.search_engines.TemplateUrlService;
+import org.chromium.chrome.browser.search_engines.TemplateUrlService.TemplateUrlServiceObserver;
+import org.chromium.content.browser.ContentViewCore;
+import org.chromium.content_public.browser.GestureStateListener;
+
+/**
+ * Manages the activation and gesture listeners for ContextualSearch on a given tab.
+ */
+public class ContextualSearchTabHelper extends EmptyTabObserver {
+    /**
+     * Notification handler for Contextual Search events.
+     */
+    private final TemplateUrlServiceObserver mTemplateUrlObserver =
+            new TemplateUrlServiceObserver() {
+                @Override
+                public void onTemplateURLServiceChanged() {
+                    onContextualSearchPrefChanged();
+                }
+            };
+
+    /**
+     * The current ContentViewCore for the Tab which this helper is monitoring.
+     */
+    private ContentViewCore mBaseContentViewCore;
+
+    /**
+     * The GestureListener used for handling events from the current ContentViewCore.
+     */
+    private GestureStateListener mGestureStateListener;
+
+    private long mNativeHelper = 0;
+
+    /**
+     * Creates a contextual search tab helper for the given tab.
+     * @param tab The tab whose contextual search actions will be handled by this helper.
+     */
+    public static void createForTab(Tab tab) {
+        new ContextualSearchTabHelper(tab);
+    }
+
+    private ContextualSearchTabHelper(Tab tab) {
+        tab.addObserver(this);
+    }
+
+    @Override
+    public void onPageLoadStarted(Tab tab) {
+        if (tab.getContentViewCore() == null) {
+            // Nothing to do yet.
+            return;
+        }
+
+        mBaseContentViewCore = tab.getContentViewCore();
+        // Add Contextual Search here in case it couldn't get added in onContentChanged() due to
+        // being too early in initialization of Chrome (ContextualSearchManager being null).
+        setContextualSearchHooks(mBaseContentViewCore);
+    }
+
+    @Override
+    public void onPageLoadFinished(Tab tab) {
+        // Native initialization happens after a page loads to ensure profile is initialized.
+        if (mNativeHelper == 0) {
+            mNativeHelper = nativeInit(tab.getProfile());
+        }
+    }
+
+    @Override
+    public void onContentChanged(Tab tab) {
+        updateHooksForNewContentViewCore(tab);
+    }
+
+    @Override
+    public void onWebContentsSwapped(Tab tab, boolean didStartLoad, boolean didFinishLoad) {
+        updateHooksForNewContentViewCore(tab);
+    }
+
+    @Override
+    public void onDestroyed(Tab tab) {
+        if (mNativeHelper != 0) {
+            nativeDestroy(mNativeHelper);
+            mNativeHelper = 0;
+        }
+        removeContextualSearchHooks(mBaseContentViewCore);
+        mBaseContentViewCore = null;
+    }
+
+    /**
+     * Should be called whenever the Tab's ContentViewCore changes. Removes hooks from the
+     * existing ContentViewCore, if necessary and then adds hooks for the new ContentViewCore.
+     * @param tab
+     */
+    private void updateHooksForNewContentViewCore(Tab tab) {
+        removeContextualSearchHooks(mBaseContentViewCore);
+        mBaseContentViewCore = tab.getContentViewCore();
+        setContextualSearchHooks(mBaseContentViewCore);
+    }
+
+    /**
+     * Sets up the Contextual Search hooks, adding or removing them depending on whether it is
+     * currently active.
+     * @param cvc The content view core to attach the gesture state listener to.
+     */
+    private void setContextualSearchHooks(ContentViewCore cvc) {
+        if (cvc == null) return;
+
+        if (isContextualSearchActive(cvc)) {
+            addContextualSearchHooks(cvc);
+        } else {
+            removeContextualSearchHooks(cvc);
+        }
+    }
+
+    /**
+     * Adds Contextual Search hooks for its client and listener to the given content view core.
+     * @param cvc The content view core to attach the gesture state listener to.
+     */
+    private void addContextualSearchHooks(ContentViewCore cvc) {
+        if (ContextualSearchFieldTrial.isEnabled(cvc.getContext().getApplicationContext())) {
+            ContextualSearchUma.logPreferenceState(
+                    ContextualSearchPolicy.getInstance(cvc.getContext()).getPromoTapsRemaining());
+        }
+        if (mGestureStateListener == null) {
+            mGestureStateListener = getContextualSearchManager(cvc).getGestureStateListener();
+            cvc.addGestureStateListener(mGestureStateListener);
+            cvc.setContextualSearchClient(getContextualSearchManager(cvc));
+            TemplateUrlService.getInstance().addObserver(mTemplateUrlObserver);
+        }
+    }
+
+    /**
+     * Removes Contextual Search hooks for its client and listener from the given content view core.
+     * @param cvc The content view core to detach the gesture state listener from.
+     */
+    private void removeContextualSearchHooks(ContentViewCore cvc) {
+        if (cvc == null) return;
+
+        if (ContextualSearchFieldTrial.isEnabled(cvc.getContext().getApplicationContext())) {
+            ContextualSearchUma.logPreferenceState(
+                    ContextualSearchPolicy.getInstance(cvc.getContext()).getPromoTapsRemaining());
+        }
+        if (mGestureStateListener != null) {
+            cvc.removeGestureStateListener(mGestureStateListener);
+            mGestureStateListener = null;
+            cvc.setContextualSearchClient(null);
+            TemplateUrlService.getInstance().removeObserver(mTemplateUrlObserver);
+        }
+    }
+
+    /**
+     * @return whether Contextual Search is enabled and active in this tab.
+     */
+    private static boolean isContextualSearchActive(ContentViewCore cvc) {
+        return !cvc.getWebContents().isIncognito() && getContextualSearchManager(cvc) != null
+            && !PrefServiceBridge.getInstance().isContextualSearchDisabled()
+            && TemplateUrlService.getInstance().isDefaultSearchEngineGoogle()
+            // Svelte and Accessibility devices are incompatible with the first-run flow and
+            // Talkback has poor interaction with tap to search (see http://crbug.com/399708 and
+            // http://crbug.com/396934).
+            // TODO(jeremycho): Handle these cases.
+            && !getContextualSearchManager(cvc).isRunningInCompatibilityMode();
+    }
+
+    /**
+     * @return the Contextual Search manager.
+     */
+    private static ContextualSearchManager getContextualSearchManager(ContentViewCore cvc) {
+        // TODO(yfriedman): Decouple this from the activity.
+        if (cvc.getContext() instanceof CompositorChromeActivity) {
+            return ((CompositorChromeActivity) cvc.getContext()).getContextualSearchManager();
+        }
+        return null;
+    }
+
+    @CalledByNative
+    private void onContextualSearchPrefChanged() {
+        setContextualSearchHooks(mBaseContentViewCore);
+    }
+
+    private native long nativeInit(Profile profile);
+    private native void nativeDestroy(long nativeContextualSearchTabHelper);
+}