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diff --git a/src/com/android/messaging/util/Trace.java b/src/com/android/messaging/util/Trace.java
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+++ b/src/com/android/messaging/util/Trace.java
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+/*
+ * Copyright (C) 2015 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 com.android.messaging.util;
+
+
+import android.annotation.TargetApi;
+import android.os.Build;
+
+/**
+ * Helper class for systrace (see http://developer.android.com/tools/help/systrace.html).<p>
+ * To enable, set log.tag.Bugle_Trace (defined by {@link #TAG} to VERBOSE before
+ * the process starts.<p>
+ * Note that this will run only on JBMR2 or later; on earlier platforms or if the log
+ * tag isn't set, calls to {@link #beginSection(String)} or {@link #endSection()} are no-ops. <p>
+ * Internally, calls dispatch to either a class that actually does work or a class that doesn't.
+ * This avoids Dalvik complaining when it loads the class on earlier platforms that the
+ * opcodes aren't available, and, according to the Dalvik team, using vtable dispatching for
+ * something like this should be faster than if (OsUtil.isAtLeast...()) on each call.
+ */
+public final class Trace {
+    private static final String TAG = "Bugle_Trace";
+    private abstract static class AbstractTrace {
+        abstract void beginSection(String sectionName);
+        abstract void endSection();
+    }
+
+    private static final AbstractTrace sTrace;
+
+    // Static initializer to pick the correct trace class to handle tracing.
+    static {
+        // Use android.util.Log instead of LogUtil here to avoid pulling in Gservices
+        // too early in app startup.
+        if (OsUtil.isAtLeastJB_MR2() &&
+                android.util.Log.isLoggable(TAG, android.util.Log.VERBOSE)) {
+            sTrace = new TraceJBMR2();
+        } else {
+            sTrace = new TraceShim();
+        }
+    }
+
+    /**
+     * Writes a trace message to indicate that a given section of code has begun. This call must
+     * be followed by a corresponding call to {@link #endSection()} on the same thread.
+     *
+     * <p class="note"> At this time the vertical bar character '|', newline character '\n', and
+     * null character '\0' are used internally by the tracing mechanism.  If sectionName contains
+     * these characters they will be replaced with a space character in the trace.
+     *
+     * @param sectionName The name of the code section to appear in the trace.  This may be at
+     * most 127 Unicode code units long.
+     */
+    public static void beginSection(String sectionName) {
+        if (LogUtil.isLoggable(TAG, LogUtil.VERBOSE)) {
+            LogUtil.v(TAG, "beginSection() " + sectionName);
+        }
+        sTrace.beginSection(sectionName);
+    }
+
+    /**
+     * Writes a trace message to indicate that a given section of code has ended. This call must
+     * be preceeded by a corresponding call to {@link #beginSection(String)}. Calling this method
+     * will mark the end of the most recently begun section of code, so care must be taken to
+     * ensure that beginSection / endSection pairs are properly nested and called from the same
+     * thread.
+     */
+    public static void endSection() {
+        sTrace.endSection();
+        if (LogUtil.isLoggable(TAG, LogUtil.VERBOSE)) {
+            LogUtil.v(TAG, "endSection()");
+        }
+    }
+
+    /**
+     * Internal class that we use if we really did enable tracing.
+     */
+    @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2)
+    private static final class TraceJBMR2 extends AbstractTrace {
+        @Override
+        void beginSection(String sectionName) {
+            android.os.Trace.beginSection(sectionName);
+        }
+
+        @Override
+        void endSection() {
+            android.os.Trace.endSection();
+        }
+    }
+
+    /**
+     * Dummy class that we use if we aren't really tracing.
+     */
+    private static final class TraceShim extends AbstractTrace {
+        @Override
+        void beginSection(String sectionName) {
+        }
+
+        @Override
+        void endSection() {
+        }
+    }
+}