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

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

Index: chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapShortWordSuppression.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapShortWordSuppression.java b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapShortWordSuppression.java
new file mode 100644
index 0000000000000000000000000000000000000000..bbd1672d4a97489aa1963a6040f4cf5e0d20377e
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/TapShortWordSuppression.java
@@ -0,0 +1,60 @@
+// 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;
+
+import android.text.TextUtils;
+
+/**
+ * Implements the policy that a Tap on a short word should be ignored.
+ * This signal could be used for suppression so we aggregate-log too.
+ */
+class TapShortWordSuppression extends ContextualSearchHeuristic {
+    private static final int TOO_SHORT_WORD_LENGTH = 3;
+
+    private final boolean mIsSuppressionEnabled;
+    private final boolean mIsConditionSatisfied;
+
+    /**
+     * Constructs a heuristic to determine if the current Tap is close to the edge of the word.
+     * @param contextualSearchContext The current {@link ContextualSearchContext} so we can figure
+     *        out what part of the word has been tapped.
+     */
+    TapShortWordSuppression(ContextualSearchContext contextualSearchContext) {
+        mIsSuppressionEnabled = ContextualSearchFieldTrial.isShortWordSuppressionEnabled();
+        mIsConditionSatisfied = isTapOnShortWord(contextualSearchContext);
+    }
+
+    @Override
+    protected boolean isConditionSatisfiedAndEnabled() {
+        return mIsSuppressionEnabled && mIsConditionSatisfied;
+    }
+
+    @Override
+    protected void logResultsSeen(boolean wasSearchContentViewSeen, boolean wasActivatedByTap) {
+        if (wasActivatedByTap) {
+            ContextualSearchUma.logTapShortWordSeen(
+                    wasSearchContentViewSeen, mIsConditionSatisfied);
+        }
+    }
+
+    @Override
+    protected boolean shouldAggregateLogForTapSuppression() {
+        return true;
+    }
+
+    @Override
+    protected boolean isConditionSatisfiedForAggregateLogging() {
+        return mIsConditionSatisfied;
+    }
+
+    /**
+     * @return Whether the tap is on a "short" word.
+     */
+    private boolean isTapOnShortWord(ContextualSearchContext contextualSearchContext) {
+        // If setup failed, don't suppress.
+        String tappedWord = contextualSearchContext.getTappedWord();
+        return !TextUtils.isEmpty(tappedWord) && tappedWord.length() <= TOO_SHORT_WORD_LENGTH;
+    }
+}