LiveSession: Use the actual, possibly redirected url as base in the M3U

This fixes playback of HLS streams where the M3U playlists use
relative paths and the main playlist is opened via a redirect.

Bug: 13174301
Change-Id: I787e1c050daddc566be4c8e3f84803d3f91eec46
diff --git a/media/libstagefright/httplive/LiveSession.cpp b/media/libstagefright/httplive/LiveSession.cpp
index 9e30ebd..687e871 100644
--- a/media/libstagefright/httplive/LiveSession.cpp
+++ b/media/libstagefright/httplive/LiveSession.cpp
@@ -623,7 +623,8 @@
         const char *url, sp<ABuffer> *out,
         int64_t range_offset, int64_t range_length,
         uint32_t block_size, /* download block size */
-        sp<DataSource> *source /* to return and reuse source */) {
+        sp<DataSource> *source, /* to return and reuse source */
+        String8 *actualUrl) {
     off64_t size;
     sp<DataSource> temp_source;
     if (source == NULL) {
@@ -719,6 +720,12 @@
     }
 
     *out = buffer;
+    if (actualUrl != NULL) {
+        *actualUrl = (*source)->getUri();
+        if (actualUrl->isEmpty()) {
+            *actualUrl = url;
+        }
+    }
 
     return OK;
 }
@@ -730,7 +737,8 @@
     *unchanged = false;
 
     sp<ABuffer> buffer;
-    status_t err = fetchFile(url, &buffer);
+    String8 actualUrl;
+    status_t err = fetchFile(url, &buffer, 0, -1, 0, NULL, &actualUrl);
 
     if (err != OK) {
         return NULL;
@@ -764,7 +772,7 @@
 #endif
 
     sp<M3UParser> playlist =
-        new M3UParser(url, buffer->data(), buffer->size());
+        new M3UParser(actualUrl.string(), buffer->data(), buffer->size());
 
     if (playlist->initCheck() != OK) {
         ALOGE("failed to parse .m3u8 playlist");
diff --git a/media/libstagefright/httplive/LiveSession.h b/media/libstagefright/httplive/LiveSession.h
index e26d024..376d451 100644
--- a/media/libstagefright/httplive/LiveSession.h
+++ b/media/libstagefright/httplive/LiveSession.h
@@ -207,7 +207,8 @@
             /* download block size */
             uint32_t block_size = 0,
             /* reuse DataSource if doing partial fetch */
-            sp<DataSource> *source = NULL);
+            sp<DataSource> *source = NULL,
+            String8 *actualUrl = NULL);
 
     sp<M3UParser> fetchPlaylist(
             const char *url, uint8_t *curPlaylistHash, bool *unchanged);