Move Android TraceEvent interface to base

content/public/android/java/src/org/chromium/content/common/TraceEvent.java

Index: content/public/android/java/src/org/chromium/content/common/TraceEvent.java
diff --git a/content/public/android/java/src/org/chromium/content/common/TraceEvent.java b/content/public/android/java/src/org/chromium/content/common/TraceEvent.java
index 2b1dac00ef52df33421763227f9787eccc589d1a..6c0356455057edf48e1103a3d6ce994ea4478827 100644
--- a/content/public/android/java/src/org/chromium/content/common/TraceEvent.java
+++ b/content/public/android/java/src/org/chromium/content/common/TraceEvent.java
@@ -4,252 +4,28 @@
 
 package org.chromium.content.common;
 
-import android.os.Build;
-import android.os.Looper;
-import android.os.MessageQueue;
-import android.os.SystemClock;
-import android.util.Log;
-import android.util.Printer;
-
-import org.chromium.base.CommandLine;
-import org.chromium.base.ThreadUtils;
-
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
-
 /**
- * Java mirror of Chrome trace event API. See base/debug/trace_event.h.  Unlike the native version,
- * Java does not have stack objects, so a TRACE_EVENT() which does both TRACE_EVENT_BEGIN() and
- * TRACE_EVENT_END() in ctor/dtor is not possible.
- * It is OK to use tracing before the native library has loaded, but such traces will
- * be ignored. (Perhaps we could devise to buffer them up in future?).
+ * Wrapper for org.chromium.base.TraceEvent to make landing cross-repository
+ * change easier. The real TraceEvent class used to be here
+ * TODO(aberent) - remove this.
  */
 public class TraceEvent {
 
-    private static volatile boolean sEnabled = false;
-
-    private static class BasicLooperMonitor implements Printer {
-        private static final String DISPATCH_EVENT_NAME =
-                "Looper.dispatchMessage";
-
-        @Override
-        public void println(final String line) {
-            if (line.startsWith(">")) {
-                beginHandling(line);
-            } else {
-                assert line.startsWith("<");
-                endHandling(line);
-            }
-        }
-
-        void beginHandling(final String line) {
-            TraceEvent.begin(DISPATCH_EVENT_NAME, line);
-        }
-
-        void endHandling(final String line) {
-            TraceEvent.end(DISPATCH_EVENT_NAME);
-        }
-    }
-
-    /**
-     * A class that records, traces and logs statistics about the UI thead's Looper.
-     * The output of this class can be used in a number of interesting ways:
-     * <p>
-     * <ol><li>
-     * When using chrometrace, there will be a near-continuous line of
-     * measurements showing both event dispatches as well as idles;
-     * </li><li>
-     * Logging messages are output for events that run too long on the
-     * event dispatcher, making it easy to identify problematic areas;
-     * </li><li>
-     * Statistics are output whenever there is an idle after a non-trivial
-     * amount of activity, allowing information to be gathered about task
-     * density and execution cadence on the Looper;
-     * </li></ol>
-     * <p>
-     * The class attaches itself as an idle handler to the main Looper, and
-     * monitors the execution of events and idle notifications. Task counters
-     * accumulate between idle notifications and get reset when a new idle
-     * notification is received.
-     */
-    private static final class IdleTracingLooperMonitor extends BasicLooperMonitor
-            implements MessageQueue.IdleHandler {
-        // Tags for dumping to logcat or TraceEvent
-        private static final String TAG = "TraceEvent.LooperMonitor";
-        private static final String IDLE_EVENT_NAME = "Looper.queueIdle";
-
-        // Calculation constants
-        private static final long FRAME_DURATION_MILLIS = 1000L / 60L; // 60 FPS
-        // A reasonable threshold for defining a Looper event as "long running"
-        private static final long MIN_INTERESTING_DURATION_MILLIS =
-                FRAME_DURATION_MILLIS;
-        // A reasonable threshold for a "burst" of tasks on the Looper
-        private static final long MIN_INTERESTING_BURST_DURATION_MILLIS =
-                MIN_INTERESTING_DURATION_MILLIS * 3;
-
-        // Stats tracking
-        private long mLastIdleStartedAt = 0L;
-        private long mLastWorkStartedAt = 0L;
-        private int mNumTasksSeen = 0;
-        private int mNumIdlesSeen = 0;
-        private int mNumTasksSinceLastIdle = 0;
-
-        // State
-        private boolean mIdleMonitorAttached = false;
-
-        // Called from within the begin/end methods only.
-        // This method can only execute on the looper thread, because that is
-        // the only thread that is permitted to call Looper.myqueue().
-        private final void syncIdleMonitoring() {
-            if (sEnabled && !mIdleMonitorAttached) {
-                // approximate start time for computational purposes
-                mLastIdleStartedAt = SystemClock.elapsedRealtime();
-                Looper.myQueue().addIdleHandler(this);
-                mIdleMonitorAttached = true;
-                Log.v(TAG, "attached idle handler");
-            } else if (mIdleMonitorAttached && !sEnabled) {
-                Looper.myQueue().removeIdleHandler(this);
-                mIdleMonitorAttached = false;
-                Log.v(TAG, "detached idle handler");
-            }
-        }
-
-        @Override
-        final void beginHandling(final String line) {
-            // Close-out any prior 'idle' period before starting new task.
-            if (mNumTasksSinceLastIdle == 0) {
-                TraceEvent.end(IDLE_EVENT_NAME);
-            }
-            mLastWorkStartedAt = SystemClock.elapsedRealtime();
-            syncIdleMonitoring();
-            super.beginHandling(line);
-        }
-
-        @Override
-        final void endHandling(final String line) {
-            final long elapsed = SystemClock.elapsedRealtime()
-                    - mLastWorkStartedAt;
-            if (elapsed > MIN_INTERESTING_DURATION_MILLIS) {
-                traceAndLog(Log.WARN, "observed a task that took "
-                        + elapsed + "ms: " + line);
-            }
-            super.endHandling(line);
-            syncIdleMonitoring();
-            mNumTasksSeen++;
-            mNumTasksSinceLastIdle++;
-        }
-
-        private static void traceAndLog(int level, String message) {
-            TraceEvent.instant("TraceEvent.LooperMonitor:IdleStats", message);
-            Log.println(level, TAG, message);
-        }
-
-        @Override
-        public final boolean queueIdle() {
-            final long now =  SystemClock.elapsedRealtime();
-            if (mLastIdleStartedAt == 0) mLastIdleStartedAt = now;
-            final long elapsed = now - mLastIdleStartedAt;
-            mNumIdlesSeen++;
-            TraceEvent.begin(IDLE_EVENT_NAME, mNumTasksSinceLastIdle + " tasks since last idle.");
-            if (elapsed > MIN_INTERESTING_BURST_DURATION_MILLIS) {
-                // Dump stats
-                String statsString = mNumTasksSeen + " tasks and "
-                        + mNumIdlesSeen + " idles processed so far, "
-                        + mNumTasksSinceLastIdle + " tasks bursted and "
-                        + elapsed + "ms elapsed since last idle";
-                traceAndLog(Log.DEBUG, statsString);
-            }
-            mLastIdleStartedAt = now;
-            mNumTasksSinceLastIdle = 0;
-            return true; // stay installed
-        }
-    }
-
-    // Holder for monitor avoids unnecessary construction on non-debug runs
-    private static final class LooperMonitorHolder {
-        private static final BasicLooperMonitor sInstance =
-                CommandLine.getInstance().hasSwitch(ContentSwitches.ENABLE_IDLE_TRACING) ?
-                        new IdleTracingLooperMonitor() : new BasicLooperMonitor();
-    }
-
-    private static long sTraceTagView;
-    private static Method sSystemPropertiesGetLongMethod;
-    private static final String PROPERTY_TRACE_TAG_ENABLEFLAGS = "debug.atrace.tags.enableflags";
-
-    static {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
-            try {
-                Class<?> traceClass = Class.forName("android.os.Trace");
-                sTraceTagView = traceClass.getField("TRACE_TAG_WEBVIEW").getLong(null);
-
-                Class<?> systemPropertiesClass = Class.forName("android.os.SystemProperties");
-                sSystemPropertiesGetLongMethod = systemPropertiesClass.getDeclaredMethod(
-                        "getLong", String.class, Long.TYPE);
-                Method addChangeCallbackMethod = systemPropertiesClass.getDeclaredMethod(
-                        "addChangeCallback", Runnable.class);
-
-                // Won't reach here if any of the above reflect lookups fail.
-                addChangeCallbackMethod.invoke(null, new Runnable() {
-                    @Override
-                    public void run() {
-                        setEnabledToMatchNative();
-                    }
-                });
-            } catch (ClassNotFoundException e) {
-                Log.e("TraceEvent", "init", e);
-            } catch (NoSuchMethodException e) {
-                Log.e("TraceEvent", "init", e);
-            } catch (IllegalArgumentException e) {
-                Log.e("TraceEvent", "init", e);
-            } catch (IllegalAccessException e) {
-                Log.e("TraceEvent", "init", e);
-            } catch (InvocationTargetException e) {
-                Log.e("TraceEvent", "init", e);
-            } catch (NoSuchFieldException e) {
-                Log.e("TraceEvent", "init", e);
-            }
-        }
-    }
-
     /**
      * Calling this will cause enabled() to be updated to match that set on the native side.
      * The native library must be loaded before calling this method.
      */
     public static void setEnabledToMatchNative() {
-        boolean enabled = nativeTraceEnabled();
-
-        if (sSystemPropertiesGetLongMethod != null) {
-            try {
-                long enabledFlags = (Long) sSystemPropertiesGetLongMethod.invoke(
-                        null, PROPERTY_TRACE_TAG_ENABLEFLAGS, 0);
-                if ((enabledFlags & sTraceTagView) != 0) {
-                    nativeStartATrace();
-                    enabled = true;
-                } else {
-                    nativeStopATrace();
-                }
-            } catch (IllegalArgumentException e) {
-                Log.e("TraceEvent", "setEnabledToMatchNative", e);
-            } catch (IllegalAccessException e) {
-                Log.e("TraceEvent", "setEnabledToMatchNative", e);
-            } catch (InvocationTargetException e) {
-                Log.e("TraceEvent", "setEnabledToMatchNative", e);
-            }
-        }
-
-        setEnabled(enabled);
+        org.chromium.base.TraceEvent.setEnabledToMatchNative();
     }
 
     /**
      * Enables or disables tracing.
      * The native library must be loaded before the first call with enabled == true.
      */
-    public static synchronized void setEnabled(boolean enabled) {
-        if (sEnabled == enabled) return;
-        sEnabled = enabled;
-        ThreadUtils.getUiThreadLooper().setMessageLogging(
-                enabled ? LooperMonitorHolder.sInstance : null);
-    }
+    public static void setEnabled(boolean enabled) {
+        org.chromium.base.TraceEvent.setEnabled(enabled);
+   }
 
     /**
      * @return True if tracing is enabled, false otherwise.
@@ -257,7 +33,7 @@ public class TraceEvent {
      * is enabled.
      */
     public static boolean enabled() {
-        return sEnabled;
+        return org.chromium.base.TraceEvent.enabled();
     }
 
     /**
@@ -265,7 +41,7 @@ public class TraceEvent {
      * @param name The name of the event.
      */
     public static void instant(String name) {
-        if (sEnabled) nativeInstant(name, null);
+        org.chromium.base.TraceEvent.instant(name);
     }
 
     /**
@@ -274,7 +50,7 @@ public class TraceEvent {
      * @param arg  The arguments of the event.
      */
     public static void instant(String name, String arg) {
-        if (sEnabled) nativeInstant(name, arg);
+        org.chromium.base.TraceEvent.instant(name, arg);
     }
 
     /**
@@ -284,7 +60,7 @@ public class TraceEvent {
      * @see #begin()
      */
     public static void startAsync(long id) {
-        if (sEnabled) nativeStartAsync(getCallerName(), id, null);
+        org.chromium.base.TraceEvent.startAsync(id);
     }
 
     /**
@@ -294,7 +70,7 @@ public class TraceEvent {
      * @see #begin()
      */
     public static void startAsync(String name, long id) {
-        if (sEnabled) nativeStartAsync(name, id, null);
+        org.chromium.base.TraceEvent.startAsync(name, id);
     }
 
     /**
@@ -305,7 +81,7 @@ public class TraceEvent {
      * @see #begin()
      */
     public static void startAsync(String name, long id, String arg) {
-        if (sEnabled) nativeStartAsync(name, id, arg);
+        org.chromium.base.TraceEvent.startAsync(name, id, arg);
     }
 
     /**
@@ -315,7 +91,7 @@ public class TraceEvent {
      * @see #finish()
      */
     public static void finishAsync(long id) {
-        if (sEnabled) nativeFinishAsync(getCallerName(), id, null);
+        org.chromium.base.TraceEvent.finishAsync(id);
     }
 
     /**
@@ -325,7 +101,7 @@ public class TraceEvent {
      * @see #begin()
      */
     public static void finishAsync(String name, long id) {
-        if (sEnabled) nativeFinishAsync(name, id, null);
+        org.chromium.base.TraceEvent.finishAsync(name,id);
     }
 
     /**
@@ -336,7 +112,7 @@ public class TraceEvent {
      * @see #begin()
      */
     public static void finishAsync(String name, long id, String arg) {
-        if (sEnabled) nativeFinishAsync(name, id, arg);
+        org.chromium.base.TraceEvent.finishAsync(name, id, arg);
     }
 
     /**
@@ -346,7 +122,7 @@ public class TraceEvent {
      * same calling context.
      */
     public static void begin() {
-        if (sEnabled) nativeBegin(getCallerName(), null);
+        org.chromium.base.TraceEvent.begin();
     }
 
     /**
@@ -354,7 +130,7 @@ public class TraceEvent {
      * @param name The name of the event.
      */
     public static void begin(String name) {
-        if (sEnabled) nativeBegin(name, null);
+        org.chromium.base.TraceEvent.begin(name);
     }
 
     /**
@@ -363,7 +139,7 @@ public class TraceEvent {
      * @param arg  The arguments of the event.
      */
     public static void begin(String name, String arg) {
-        if (sEnabled) nativeBegin(name, arg);
+        org.chromium.base.TraceEvent.begin(name, arg);
     }
 
     /**
@@ -371,7 +147,7 @@ public class TraceEvent {
      * for more information.
      */
     public static void end() {
-        if (sEnabled) nativeEnd(getCallerName(), null);
+        org.chromium.base.TraceEvent.end();
     }
 
     /**
@@ -379,7 +155,7 @@ public class TraceEvent {
      * @param name The name of the event.
      */
     public static void end(String name) {
-        if (sEnabled) nativeEnd(name, null);
+        org.chromium.base.TraceEvent.end(name);
     }
 
     /**
@@ -388,30 +164,6 @@ public class TraceEvent {
      * @param arg  The arguments of the event.
      */
     public static void end(String name, String arg) {
-        if (sEnabled) nativeEnd(name, arg);
+        org.chromium.base.TraceEvent.end(name, arg);
     }
-
-    private static String getCallerName() {
-        // This was measured to take about 1ms on Trygon device.
-        StackTraceElement[] stack = java.lang.Thread.currentThread().getStackTrace();
-
-        // Commented out to avoid excess call overhead, but these lines can be useful to debug
-        // exactly where the TraceEvent's client is on the callstack.
-        //  int index = 0;
-        //  while (!stack[index].getClassName().equals(TraceEvent.class.getName())) ++index;
-        //  while (stack[index].getClassName().equals(TraceEvent.class.getName())) ++index;
-        //  System.logW("TraceEvent caller is at stack index " + index);
-
-        // '4' Was derived using the above commented out code snippet.
-        return stack[4].getClassName() + "." + stack[4].getMethodName();
-    }
-
-    private static native boolean nativeTraceEnabled();
-    private static native void nativeStartATrace();
-    private static native void nativeStopATrace();
-    private static native void nativeInstant(String name, String arg);
-    private static native void nativeBegin(String name, String arg);
-    private static native void nativeEnd(String name, String arg);
-    private static native void nativeStartAsync(String name, long id, String arg);
-    private static native void nativeFinishAsync(String name, long id, String arg);
 }