Easy switching of logging for TextClassifier

This way there is a single switch for detailed logging vs summarised
logging. We can keep the switch on in development but limit the logs
in production devices.

Test: manually tested log switch turned on/off.
Change-Id: I8ad291b19554f393a05fbc7cae3d545163d21a99

core/java/android/view/textclassifier/Log.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.view.textclassifier;
+
+import android.util.Slog;
+
+/**
+ * Logging for android.view.textclassifier package.
+ */
+final class Log {
+
+    /**
+     * true: Enables full logging.
+     * false: Limits logging to debug level.
+     */
+    private static final boolean ENABLE_FULL_LOGGING = false;
+
+    private Log() {}
+
+    public static void d(String tag, String msg) {
+        Slog.d(tag, msg);
+    }
+
+    public static void e(String tag, String msg, Throwable tr) {
+        if (ENABLE_FULL_LOGGING) {
+            Slog.e(tag, msg, tr);
+        } else {
+            final String trString = (tr != null) ? tr.getClass().getSimpleName() : "??";
+            Slog.d(tag, String.format("%s (%s)", msg, trString));
+        }
+    }
+}

core/java/android/view/textclassifier/TextClassifierImpl.java

@@ -35,7 +35,6 @@ import android.text.TextUtils;
 import android.text.method.WordIterator;
 import android.text.style.ClickableSpan;
 import android.text.util.Linkify;
-import android.util.Log;
 import android.util.Patterns;
 import android.view.View;
 import android.widget.TextViewMetrics;
@@ -163,7 +162,7 @@ final class TextClassifierImpl implements TextClassifier {
             }
         } catch (Throwable t) {
             // Avoid throwing from this method. Log the error.
-            Log.e(LOG_TAG, "Error getting assist info.", t);
+            Log.e(LOG_TAG, "Error getting text classification info.", t);
         }
         // Getting here means something went wrong, return a NO_OP result.
         return TextClassifier.NO_OP.classifyText(