BufferQueue: add a setMaxAcquiredBufferCount check

This change adds a check to verify the validity of the value passed to
setMaxAcquiredBufferCount.

Change-Id: I39730557aa58261e678bd6e4fce11bab78e98362
diff --git a/libs/gui/BufferQueue.cpp b/libs/gui/BufferQueue.cpp
index 4640149..2eee6f5 100644
--- a/libs/gui/BufferQueue.cpp
+++ b/libs/gui/BufferQueue.cpp
@@ -974,6 +974,11 @@
 status_t BufferQueue::setMaxAcquiredBufferCount(int maxAcquiredBuffers) {
     ATRACE_CALL();
     Mutex::Autolock lock(mMutex);
+    if (maxAcquiredBuffers < 1 || maxAcquiredBuffers > MAX_MAX_ACQUIRED_BUFFERS) {
+        ST_LOGE("setMaxAcquiredBufferCount: invalid count specified: %d",
+                maxAcquiredBuffers);
+        return BAD_VALUE;
+    }
     if (mConnectedApi != NO_CONNECTED_API) {
         return INVALID_OPERATION;
     }