MediaCodec refactoring part 1-a: buffers become separate class

MediaCodecBuffer is meant to replace ABuffer and MediaBuffer in
communication between framework components. As the first step, replace
use of ABuffer in MediaCodec with MediaCodecBuffer, and adjust related
classes accordingly.

MediaCodec.getBuffer() and related APIs now returns MediaCodecBuffers;
thus change MediaCodec clients to use MediaCodecBuffer accordingly.

Test: manually tested for key use cases (Camera, YouTube and Play Movies)
Change-Id: Iba7ce131645e75ce5ddbf497fb793ab38b7f245b
diff --git a/media/ndk/NdkMediaCodec.cpp b/media/ndk/NdkMediaCodec.cpp
index 3d1eca1..22c90e2 100644
--- a/media/ndk/NdkMediaCodec.cpp
+++ b/media/ndk/NdkMediaCodec.cpp
@@ -30,10 +30,10 @@
 
 #include <media/stagefright/foundation/ALooper.h>
 #include <media/stagefright/foundation/AMessage.h>
-#include <media/stagefright/foundation/ABuffer.h>
 
 #include <media/stagefright/MediaCodec.h>
 #include <media/stagefright/MediaErrors.h>
+#include <media/MediaCodecBuffer.h>
 
 using namespace android;
 
@@ -268,13 +268,17 @@
 
 EXPORT
 uint8_t* AMediaCodec_getInputBuffer(AMediaCodec *mData, size_t idx, size_t *out_size) {
-    android::Vector<android::sp<android::ABuffer> > abufs;
+    android::Vector<android::sp<android::MediaCodecBuffer> > abufs;
     if (mData->mCodec->getInputBuffers(&abufs) == 0) {
         size_t n = abufs.size();
         if (idx >= n) {
             ALOGE("buffer index %zu out of range", idx);
             return NULL;
         }
+        if (abufs[idx] == NULL) {
+            ALOGE("buffer index %zu is NULL", idx);
+            return NULL;
+        }
         if (out_size != NULL) {
             *out_size = abufs[idx]->capacity();
         }
@@ -286,7 +290,7 @@
 
 EXPORT
 uint8_t* AMediaCodec_getOutputBuffer(AMediaCodec *mData, size_t idx, size_t *out_size) {
-    android::Vector<android::sp<android::ABuffer> > abufs;
+    android::Vector<android::sp<android::MediaCodecBuffer> > abufs;
     if (mData->mCodec->getOutputBuffers(&abufs) == 0) {
         size_t n = abufs.size();
         if (idx >= n) {