Add Thread::isRunning and Condition::signal(WakeUpType)

The signal() method is useful to choose whether to wake up one or
all threads.

Change-Id: I062ab6d3ddd306a9fb735549ea140e2a76eed75a
diff --git a/include/utils/Thread.h b/include/utils/Thread.h
index 4a34abd..df30611 100644
--- a/include/utils/Thread.h
+++ b/include/utils/Thread.h
@@ -67,6 +67,9 @@
     // Do not call from this object's thread; will return WOULD_BLOCK in that case.
             status_t    join();
 
+    // Indicates whether this thread is running or not.
+            bool        isRunning() const;
+
 #ifdef HAVE_ANDROID_OS
     // Return the thread's kernel ID, same as the thread itself calling gettid() or
     // androidGetTid(), or -1 if the thread is not running.