surfaceflinger: add support for gralloc dump hooks

Change-Id: Ib6f539ed0132b70d040d653c03d52cc04249ac3c
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index 4af274b..4a3b20d 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -120,6 +120,11 @@
                     l.displayFrame.left, l.displayFrame.top, l.displayFrame.right, l.displayFrame.bottom);
             result.append(buffer);
         }
+
+    }
+    if (mHwc && mHwc->common.version >= 1 && mHwc->dump) {
+        mHwc->dump(mHwc, buffer, SIZE);
+        result.append(buffer);
     }
 }