Support JellyBean MR2 style of systrace

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

 // Copyright (c) 2012 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.content.common;
 
 import android.os.Build;
 import android.os.Looper;
 import android.util.Log;
 import android.util.Printer;
@@ skipping 19 matching lines @@
         public void println(String line) {
             if (line.startsWith(">>>>>")) {
                 TraceEvent.begin(NAME, line);
             } else {
                 assert line.startsWith("<<<<<");
                 TraceEvent.end(NAME);
             }
         }
     }
 
+    static {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
+            try {
+                Class<?> systemPropertiesClass = Class.forName("android.os.SystemProperties");
+                Method addChangeCallbackMethod = systemPropertiesClass.getDeclaredMethod(
+                        "addChangeCallback", Runnable.class);
+                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);
+            }
+        }
+    }
+
     /**
      * 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 (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
             try {
                 Class<?> traceClass = Class.forName("android.os.Trace");
-                Method m = traceClass.getDeclaredMethod("isTagEnabled", Long.TYPE);
-                Field f = traceClass.getField("TRACE_TAG_VIEW");
-                boolean atraceEnabled = (Boolean) m.invoke(traceClass, f.getLong(null));
-                if (atraceEnabled) nativeInitATrace();
-                enabled = enabled || atraceEnabled;
+                long traceTagView = traceClass.getField("TRACE_TAG_VIEW").getLong(null);
+                String propertyTraceTagEnableFlags = (String)traceClass.getField(

[Jay Civelli, 2013/02/13 18:24:02]

Nit: missing space after (String)

[Xianzhu, 2013/02/13 21:50:17]

Done.

+                        "PROPERTY_TRACE_TAG_ENABLEFLAGS").get(null);
+
+                Class<?> systemPropertiesClass = Class.forName("android.os.SystemProperties");
+                Method systemPropertiesGetIntMethod = systemPropertiesClass.getDeclaredMethod(
+                        "getInt", String.class, Integer.TYPE);
+                int enabledTags = (Integer) systemPropertiesGetIntMethod.invoke(

[Jay Civelli, 2013/02/13 18:24:02]

Nit: should it be named enableFlags?

[Xianzhu, 2013/02/13 21:50:17]

Done.

+                        null, propertyTraceTagEnableFlags, 0);
+                Log.d("TraceEvent", "New enabled tags: " + enabledTags);
+                if ((enabledTags & traceTagView) != 0) {
+                    nativeStartATrace();
+                    enabled = true;
+                } else {
+                    nativeStopATrace();
+                }
             } catch (ClassNotFoundException e) {
                 Log.e("TraceEvent", "setEnabledToMatchNative", e);
             } catch (NoSuchMethodException e) {
                 Log.e("TraceEvent", "setEnabledToMatchNative", e);
             } catch (NoSuchFieldException e) {
                 Log.e("TraceEvent", "setEnabledToMatchNative", e);
             } catch (IllegalArgumentException e) {
                 Log.e("TraceEvent", "setEnabledToMatchNative", e);
             } catch (IllegalAccessException e) {
                 Log.e("TraceEvent", "setEnabledToMatchNative", e);
@@ skipping 164 matching lines @@
         //  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 nativeInitATrace();
+    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);
 }