Backed out changeset c5285ff72ac4 (bug 1439433) for build bustage. CL…

…OSED TREE

dom/media/FileBlockCache.cpp

@@ -454,9 +454,7 @@ nsresult FileBlockCache::Read(int64_t aOffset,
     // If the block is not yet written to file, we can just read from
     // the memory buffer, otherwise we need to read from file.
     int32_t bytesRead = 0;
-    MOZ_ASSERT(!mBlockChanges.IsEmpty());
-    MOZ_ASSERT(blockIndex < mBlockChanges.Length());
-    RefPtr<BlockChange> change = mBlockChanges.SafeElementAt(blockIndex);
+    RefPtr<BlockChange> change = mBlockChanges[blockIndex];
     if (change && change->IsWrite()) {
       // Block isn't yet written to file. Read from memory buffer.
       const uint8_t* blockData = change->mData.get();
@@ -470,7 +468,7 @@ nsresult FileBlockCache::Read(int64_t aOffset,
         // is resolved when MoveBlock() is called, and the move's source's
         // block could be have itself been subject to a move (or write)
         // which happened *after* this move was recorded.
-        blockIndex = change->mSourceBlockIndex;
+        blockIndex = mBlockChanges[blockIndex]->mSourceBlockIndex;
       }
       // Block has been written to file, either as the source block of a move,
       // or as a stable (all changes made) block. Read the data directly