Free resources only from the GL context thread.

Bug #3179882

Resources were freed following garbage collections on a worker thread.
This worker thread had no EGL context, which would cause the renderer
to incorrectly assume that the memory was liberated.

Change-Id: Ifdb51f94ddf42641e8654522787bfac532976c7c

libs/hwui/Caches.cpp

@@ -94,6 +94,16 @@ void Caches::dumpMemoryUsage() {
     LOGD("\n");
 }
 
+///////////////////////////////////////////////////////////////////////////////
+// Memory management
+///////////////////////////////////////////////////////////////////////////////
+
+void Caches::clearGarbage() {
+    textureCache.clearGarbage();
+    gradientCache.clearGarbage();
+    pathCache.clearGarbage();
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 // VBO
 ///////////////////////////////////////////////////////////////////////////////