vr_hwc: Address ion buffer leakage

Problem:
system is running out of memory while switching between apps back and forth.

Root-cause:
vr_hwc is leaking ion buffers by holding an unreleased reference.

Solution:
No need to register the buffer when getting buffer info. This removes the
additional (unreleased) reference on the buffer.

Test: Validated vr_hwc is no longer leaking ion buffers when switching
      apps.
Bug: 36449218

Change-Id: I1c1c5d2cca35c50a4bcbcf7b879d37914b8d835f
diff --git a/services/vr/vr_window_manager/composer/impl/vr_hwc.cpp b/services/vr/vr_window_manager/composer/impl/vr_hwc.cpp
index d142729..b5724ca 100644
--- a/services/vr/vr_window_manager/composer/impl/vr_hwc.cpp
+++ b/services/vr/vr_window_manager/composer/impl/vr_hwc.cpp
@@ -49,12 +49,6 @@
   int32_t format = 0;
 
   GraphicBufferMapper& mapper = GraphicBufferMapper::get();
-  // Need to register |handle| otherwise we can't read its properties.
-  if (mapper.registerBuffer(handle) != OK) {
-    ALOGE("Failed to register buffer");
-    return nullptr;
-  }
-
   if (mapper.getDimensions(handle, &width, &height) ||
       mapper.getStride(handle, &stride) ||
       mapper.getFormat(handle, &format) ||