[Contextual Search] Trigger translation on long-press.

Adds translation one-box triggering when the user selects
using long-press.  This currently requires server-side
auto-detection of the source language, but it should not
over-trigger due to a feature of the one-box (suppressed
when the source and target text ends up matching).

Adds a separate flag to control disabling this feature,
currently default-enabled.

BUG=413717

Review URL: https://codereview.chromium.org/1463583004

Cr-Commit-Position: refs/heads/master@{#361231}

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

@@ -33,12 +33,16 @@ public class ContextualSearchFieldTrial {
     // Translation.
     @VisibleForTesting
     static final String DISABLE_FORCE_TRANSLATION_ONEBOX = "disable_force_translation_onebox";
+    @VisibleForTesting
+    static final String DISABLE_AUTO_DETECT_TRANSLATION_ONEBOX =
+            "disable_auto_detect_translation_onebox";
 
     // Cached values to avoid repeated and redundant JNI operations.
     private static Boolean sEnabled;
     private static Boolean sIsPeekPromoEnabled;
     private static Integer sPeekPromoMaxCount;
     private static Boolean sDisableForceTranslationOnebox;
+    private static Boolean sDisableAutoDetectTranslationOnebox;
 
     /**
      * Don't instantiate.
@@ -139,6 +143,18 @@ public class ContextualSearchFieldTrial {
         return sDisableForceTranslationOnebox.booleanValue();
     }
 
+    /**
+     * @return Whether forcing a translation Onebox based on auto-detection of the source language
+     *         is disabled.
+     */
+    static boolean disableAutoDetectTranslationOnebox() {
+        if (sDisableAutoDetectTranslationOnebox == null) {
+            sDisableAutoDetectTranslationOnebox = getBooleanParam(
+                    DISABLE_AUTO_DETECT_TRANSLATION_ONEBOX);
+        }
+        return sDisableAutoDetectTranslationOnebox.booleanValue();
+    }
+
     // --------------------------------------------------------------------------------------------
     // Helpers.
     // --------------------------------------------------------------------------------------------

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

@@ -492,7 +492,7 @@ public class ContextualSearchManager extends ContextualSearchObservable
             boolean shouldPrefetch = mPolicy.shouldPrefetchSearchResult(isTap);
             mSearchRequest = new ContextualSearchRequest(mSelectionController.getSelectedText(),
                     null, shouldPrefetch);
-            // TODO(donnd): figure out a way to do translation on long-press selections.
+            forceAutoDetectTranslateUnlessDisabled(mSearchRequest);
             mDidStartLoadingResolvedSearchRequest = false;
             mSearchPanel.displaySearchTerm(mSelectionController.getSelectedText());
             if (shouldPrefetch) loadSearchUrl();
@@ -738,16 +738,7 @@ public class ContextualSearchManager extends ContextualSearchObservable
             boolean shouldPreload = !doPreventPreload && mPolicy.shouldPrefetchSearchResult(true);
             mSearchRequest = new ContextualSearchRequest(searchTerm, alternateTerm, shouldPreload);
             // Trigger translation, if enabled.
-            if (!contextLanguage.isEmpty()) {
-                if (mPolicy.needsTranslation(contextLanguage, getReadableLanguages())) {
-                    boolean doForceTranslate = !mPolicy.disableForceTranslationOnebox();
-                    if (doForceTranslate) {
-                        mSearchRequest.forceTranslation(contextLanguage,
-                                mPolicy.bestTargetLanguage(getWritableLanguages()));
-                    }
-                    ContextualSearchUma.logTranslateOnebox(doForceTranslate);
-                }
-            }
+            forceTranslateIfNeeded(mSearchRequest, contextLanguage);
             mDidStartLoadingResolvedSearchRequest = false;
             if (mSearchPanel.isContentShowing()) {
                 mSearchRequest.setNormalPriority();
@@ -797,6 +788,7 @@ public class ContextualSearchManager extends ContextualSearchObservable
 
     // ============================================================================================
     // Translation support
+    // TODO(donnd): move to a separate file.
     // ============================================================================================
 
     /**
@@ -871,6 +863,48 @@ public class ContextualSearchManager extends ContextualSearchObservable
         return new Locale(trimmedLocale).getLanguage();
     }
 
+    /**
+     * Force translation from the given language for the current search request,
+     * unless disabled by experiment.  Also log whenever conditions are right to translate.
+     * @param searchRequest The search request to force translation upon.
+     * @param sourceLanguage The language to translate from, or an empty string if not known.
+     */
+    private void forceTranslateIfNeeded(ContextualSearchRequest searchRequest,
+            String sourceLanguage) {
+        if (!TextUtils.isEmpty(sourceLanguage)) {
+            if (mPolicy.needsTranslation(sourceLanguage, getReadableLanguages())) {
+                boolean doForceTranslate = !mPolicy.disableForceTranslationOnebox();
+                if (doForceTranslate && searchRequest != null) {
+                    searchRequest.forceTranslation(sourceLanguage,
+                            mPolicy.bestTargetLanguage(getWritableLanguages()));
+                }
+                // Log that conditions were right for translation, even though it may be disabled
+                // for an experiment so we can compare with the counter factual data.
+                ContextualSearchUma.logTranslateOnebox(doForceTranslate);
+            }
+        }
+    }
+
+    /**
+     * Force auto-detect translation for the current search request unless disabled by experiment.
+     * Also log that conditions are right to translate.
+     * @param searchRequest The search request to force translation upon.
+     */
+    private void forceAutoDetectTranslateUnlessDisabled(ContextualSearchRequest searchRequest) {
+        // Always trigger translation using auto-detect when we're not resolving,
+        // unless disabled by policy.
+        boolean shouldAutoDetectTranslate = !mPolicy.disableAutoDetectTranslationOnebox();
+        if (shouldAutoDetectTranslate && searchRequest != null) {
+            // The translation one-box won't actually show when the source text ends up being
+            // the same as the target text, so we err on over-triggering.
+            searchRequest.forceAutoDetectTranslation(
+                    mPolicy.bestTargetLanguage(getWritableLanguages()));
+        }
+        // Log that conditions were right for translation, even though it may be disabled
+        // for an experiment so we can compare with the counter factual data.
+        ContextualSearchUma.logTranslateOnebox(shouldAutoDetectTranslate);
+    }
+
     // ============================================================================================
     // OverlayContentDelegate
     // ============================================================================================

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

@@ -471,6 +471,16 @@ class ContextualSearchPolicy {
         return ContextualSearchFieldTrial.disableForceTranslationOnebox();
     }
 
+    /**
+     * @return Whether forcing a translation Onebox based on auto-detection of the source language
+     *         is disabled.
+     */
+    boolean disableAutoDetectTranslationOnebox() {
+        if (disableForceTranslationOnebox()) return true;
+
+        return ContextualSearchFieldTrial.disableAutoDetectTranslationOnebox();
+    }
+
     /**
      * Sets the limit for the tap triggered promo.
      */

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

@@ -160,6 +160,15 @@ class ContextualSearchRequest {
         mNormalPriorityUri = makeTranslateUri(mNormalPriorityUri, sourceLanguage, targetLanguage);
     }
 
+    /**
+     * Adds translation parameters that will trigger auto-detection of the source language.
+     * @param targetLanguage The language the that the user prefers.
+     */
+    void forceAutoDetectTranslation(String targetLanguage) {
+        // Use the empty string for the source language in order to trigger auto-detect.
+        forceTranslation("", targetLanguage);
+    }
+
     /**
      * @return Whether translation was forced for this request.
      */

chrome/android/javatests/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManagerTest.java

@@ -2585,4 +2585,51 @@ public class ContextualSearchManagerTest extends ChromeActivityTestCaseBase<Chro
         // Make sure we did not try to trigger translate.
         assertFalse(mManager.getRequest().isTranslationForced());
     }
+
+    /**
+     * Tests that a long-press does trigger translation.
+     */
+    @SmallTest
+    @Feature({"ContextualSearch"})
+    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
+    public void testLongpressTranslates() throws InterruptedException, TimeoutException {
+        // LongPress on any word should trigger translation.
+        simulateLongPressSearch("search");
+
+        // Make sure we did try to trigger translate.
+        assertTrue(mManager.getRequest().isTranslationForced());
+    }
+
+    /**
+     * Tests that a long-press does trigger translation.
+     */
+    @SmallTest
+    @Feature({"ContextualSearch"})
+    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
+    @CommandLineFlags.Add(ContextualSearchFieldTrial.DISABLE_AUTO_DETECT_TRANSLATION_ONEBOX
+            + "=true")
+    public void testLongpressAutoDetectDisabledDoesNotTranslate()
+            throws InterruptedException, TimeoutException {
+        // Unless disabled, LongPress on any word should trigger translation.
+        simulateLongPressSearch("search");
+
+        // Make sure we did not try to trigger translate.
+        assertFalse(mManager.getRequest().isTranslationForced());
+    }
+
+    /**
+     * Tests that a long-press does trigger translation.
+     */
+    @SmallTest
+    @Feature({"ContextualSearch"})
+    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
+    @CommandLineFlags.Add(ContextualSearchFieldTrial.DISABLE_FORCE_TRANSLATION_ONEBOX + "=true")
+    public void testLongpressTranslateDisabledDoesNotTranslate()
+            throws InterruptedException, TimeoutException {
+        // Unless disabled, LongPress on any word should trigger translation.
+        simulateLongPressSearch("search");
+
+        // Make sure we did not try to trigger translate.
+        assertFalse(mManager.getRequest().isTranslationForced());
+    }
 }