Watch for SurfaceFlinger death

The ComposerService object wasn't watching for SurfaceFlinger
restarts, which doesn't usually matter because the app framework
restarts when SurfaceFlinger dies.  However, mediaserver continues
to run, which means its ComposerService object was trying to use
a dead handle, and playback of DRM movies was failing.

This adds a DeathRecipient listener and some logic to re-establish
the SurfaceFlinger connection.

Bug 6645813

Change-Id: I07581b881d3835601aa57d5358c8259d93bc4515

1 files changed, 14 insertions, 1 deletions

diff --git a/include/private/gui/ComposerService.h b/include/private/gui/ComposerService.h
index c2761b8..ff2f9bf 100644
--- a/include/private/gui/ComposerService.h
+++ b/include/private/gui/ComposerService.h
@@ -33,13 +33,26 @@ class ISurfaceComposer;
 
 // ---------------------------------------------------------------------------
 
+// This holds our connection to the composer service (i.e. SurfaceFlinger).
+// If the remote side goes away, we will re-establish the connection.
+// Users of this class should not retain the value from
+// getComposerService() for an extended period.
+//
+// (It's not clear that using Singleton is useful here anymore.)
 class ComposerService : public Singleton<ComposerService>
 {
-    // these are constants
     sp<ISurfaceComposer> mComposerService;
+    sp<IBinder::DeathRecipient> mDeathObserver;
+    Mutex mLock;
+
     ComposerService();
+    void connectLocked();
+    void composerServiceDied();
     friend class Singleton<ComposerService>;
 public:
+
+    // Get a connection to the Composer Service.  This will block until
+    // a connection is established.
     static sp<ISurfaceComposer> getComposerService();
 };