aac: set initial timestamp to zero

Bug: 127405861
Test: bug repro steps
Change-Id: Id080eeb2345c19651329da3a6b7d7928a9aa3463
(cherry picked from commit 19da254e6a07c909241db2ff2cd8338059bf7745)
(cherry picked from commit bddfba21c65eb7f1cc0770eb2eb78eb8156026d5)
diff --git a/media/codecs/aac/C2SoftAacEnc.cpp b/media/codecs/aac/C2SoftAacEnc.cpp
index 3380686..889016a 100644
--- a/media/codecs/aac/C2SoftAacEnc.cpp
+++ b/media/codecs/aac/C2SoftAacEnc.cpp
@@ -153,7 +153,7 @@
       mSentCodecSpecificData(false),
       mInputTimeSet(false),
       mInputSize(0),
-      mInputTimeUs(-1ll),
+      mInputTimeUs(0),
       mSignalledError(false) {
 }
 
@@ -178,7 +178,7 @@
     mSentCodecSpecificData = false;
     mInputTimeSet = false;
     mInputSize = 0u;
-    mInputTimeUs = -1ll;
+    mInputTimeUs = 0;
     mSignalledError = false;
     return C2_OK;
 }
@@ -196,6 +196,7 @@
     mSentCodecSpecificData = false;
     mInputTimeSet = false;
     mInputSize = 0u;
+    mInputTimeUs = 0;
     return C2_OK;
 }
 
@@ -500,6 +501,7 @@
     mSentCodecSpecificData = false;
     mInputTimeSet = false;
     mInputSize = 0u;
+    mInputTimeUs = 0;
 
     // TODO: we don't have any pending work at this time to drain.
     return C2_OK;