[TTS] Add some initial signals for Tap in content.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapWordLengthSuppression.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapWordLengthSuppression.java b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapWordLengthSuppression.java
new file mode 100644
index 0000000000000000000000000000000000000000..11a039de830d2a629a4e21e7a67e381551228cf9
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapWordLengthSuppression.java
@@ -0,0 +1,75 @@
+// Copyright 2017 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.text.TextUtils;
+
+/**
+ * Implements signals for Taps on short and long words.
+ * This signal could be used for suppression when the word is short, so we aggregate-log too.
+ * We log CTR to UMA for Taps on both short and long words.
+ */
+class TapWordLengthSuppression extends ContextualSearchHeuristic {
+    private static final int MAXIMUM_SHORT_WORD_LENGTH = 3;
+    private static final int MAXIMUM_NOT_LONG_WORD_LENGTH = 9;
+
+    private final boolean mIsShortWordSuppressionEnabled;
+    private final boolean mIsNotLongWordSuppressionEnabled;
+    private final boolean mIsShortWordConditionSatisfied;
+    private final boolean mIsNotLongWordConditionSatisfied;
+
+    /**
+     * Constructs a heuristic to categorize the Tap based on word length of the tapped word.
+     * @param contextualSearchContext The current {@link ContextualSearchContext} so we can inspect
+     *        the word tapped.
+     */
+    TapWordLengthSuppression(ContextualSearchContext contextualSearchContext) {
+        mIsShortWordSuppressionEnabled = ContextualSearchFieldTrial.isShortWordSuppressionEnabled();
+        mIsNotLongWordSuppressionEnabled =
+                ContextualSearchFieldTrial.isNotLongWordSuppressionEnabled();
+        mIsShortWordConditionSatisfied =
+                !isTapOnWordLongerThan(MAXIMUM_SHORT_WORD_LENGTH, contextualSearchContext);
+        mIsNotLongWordConditionSatisfied =
+                !isTapOnWordLongerThan(MAXIMUM_NOT_LONG_WORD_LENGTH, contextualSearchContext);
+    }
+
+    @Override
+    protected boolean isConditionSatisfiedAndEnabled() {
+        return mIsShortWordSuppressionEnabled && mIsShortWordConditionSatisfied
+                || mIsNotLongWordSuppressionEnabled && mIsNotLongWordConditionSatisfied;
+    }
+
+    @Override
+    protected void logResultsSeen(boolean wasSearchContentViewSeen, boolean wasActivatedByTap) {
+        if (wasActivatedByTap) {
+            ContextualSearchUma.logTapShortWordSeen(
+                    wasSearchContentViewSeen, mIsShortWordConditionSatisfied);
+            // Log CTR of long words, since not-long word CTR is probably not useful.
+            ContextualSearchUma.logTapLongWordSeen(
+                    wasSearchContentViewSeen, !mIsNotLongWordConditionSatisfied);
+        }
+    }
+
+    @Override
+    protected boolean shouldAggregateLogForTapSuppression() {
+        return true;
+    }
+
+    @Override
+    protected boolean isConditionSatisfiedForAggregateLogging() {
+        // Short-word suppression is a good candidate for aggregate logging of overall suppression.
+        return mIsShortWordConditionSatisfied;
+    }
+
+    /**
+     * @return Whether the tap is on a word longer than the given word length maximum.
+     */
+    private boolean isTapOnWordLongerThan(
+            int maxWordLength, ContextualSearchContext contextualSearchContext) {
+        // If setup failed, don't suppress.
+        String tappedWord = contextualSearchContext.getTappedWord();
+        return !TextUtils.isEmpty(tappedWord) && tappedWord.length() > maxWordLength;
+    }
+}