Frameworks/base: Stop profiling on uncaught exception

When "handling" an uncaught exception, make an attempt to stop
profiling. In case profiling was active, this will avoid losing
the profiling buffer.

Bug: 26291225
Change-Id: Ie5f5517b46ed89d0456a4aac9d4ff3b713d1d8aa

core/java/android/app/ActivityThread.java

@@ -4660,6 +4660,16 @@ public final class ActivityThread {
         }
     }
 
+    /**
+     * Public entrypoint to stop profiling. This is required to end profiling when the app crashes,
+     * so that profiler data won't be lost.
+     *
+     * @hide
+     */
+    public void stopProfiling() {
+        mProfiler.stopProfiling();
+    }
+
     static final void handleDumpHeap(boolean managed, DumpHeapData dhd) {
         if (managed) {
             try {

core/java/com/android/internal/os/RuntimeInit.java

@@ -86,6 +86,13 @@ public class RuntimeInit {
                     Clog_e(TAG, message.toString(), e);
                 }
 
+                // Try to end profiling. If a profiler is running at this point, and we kill the
+                // process (below), the in-memory buffer will be lost. So try to stop, which will
+                // flush the buffer. (This makes method trace profiling useful to debug crashes.)
+                if (ActivityThread.currentActivityThread() != null) {
+                    ActivityThread.currentActivityThread().stopProfiling();
+                }
+
                 // Bring up crash dialog, wait for it to be dismissed
                 ActivityManagerNative.getDefault().handleApplicationCrash(
                         mApplicationObject, new ApplicationErrorReport.CrashInfo(e));