Add additional accessors to IonBuffer and BufferHubBuffer.

- Add accessor to underlying GraphicBuffer in IonBuffer.
- Add const accessors to underlying IonBuffer(s) in BufferHubBuffer.

Bug: 36401174
Test: bufferhub_tests; buffer_hub_queue-test
Change-Id: I24a6c19b141bb50ffa06e861a4533e10d55b5b20
diff --git a/libs/vr/libbufferhub/include/private/dvr/buffer_hub_client.h b/libs/vr/libbufferhub/include/private/dvr/buffer_hub_client.h
index aacc385..dfeed50 100644
--- a/libs/vr/libbufferhub/include/private/dvr/buffer_hub_client.h
+++ b/libs/vr/libbufferhub/include/private/dvr/buffer_hub_client.h
@@ -94,9 +94,12 @@
   }
 
   IonBuffer* buffer() { return &slices_[0]; }
+  const IonBuffer* buffer() const { return &slices_[0]; }
+
   // If index is greater than or equal to slice_count(), the result is
   // undefined.
   IonBuffer* slice(size_t index) { return &slices_[index]; }
+  const IonBuffer* slice(size_t index) const { return &slices_[index]; }
 
   int slice_count() const { return static_cast<int>(slices_.size()); }
   int id() const { return id_; }
@@ -171,9 +174,8 @@
   int Post(const LocalHandle& ready_fence) {
     return Post(ready_fence, nullptr, 0);
   }
-  template <
-      typename Meta,
-      typename = typename std::enable_if<!std::is_void<Meta>::value>::type>
+  template <typename Meta, typename = typename std::enable_if<
+                               !std::is_void<Meta>::value>::type>
   int Post(const LocalHandle& ready_fence, const Meta& meta) {
     return Post(ready_fence, &meta, sizeof(meta));
   }
diff --git a/libs/vr/libbufferhub/include/private/dvr/ion_buffer.h b/libs/vr/libbufferhub/include/private/dvr/ion_buffer.h
index e449cbd..ffc42d6 100644
--- a/libs/vr/libbufferhub/include/private/dvr/ion_buffer.h
+++ b/libs/vr/libbufferhub/include/private/dvr/ion_buffer.h
@@ -60,21 +60,20 @@
   int LockYUV(int usage, int x, int y, int width, int height,
               struct android_ycbcr* yuv);
   int Unlock();
-  buffer_handle_t handle() const { if (buffer_.get()) return buffer_->handle;
-                                   else return nullptr; }
-  int width() const { if (buffer_.get()) return buffer_->getWidth();
-                      else return 0; }
-  int height() const { if (buffer_.get()) return buffer_->getHeight();
-                       else return 0; }
-  int layer_count() const { if (buffer_.get()) return buffer_->getLayerCount();
-                            else return 0; }
-  int stride() const { if (buffer_.get()) return buffer_->getStride();
-                       else return 0; }
+
+  const sp<GraphicBuffer>& buffer() const { return buffer_; }
+  buffer_handle_t handle() const {
+    return buffer_.get() ? buffer_->handle : nullptr;
+  }
+  int width() const { return buffer_.get() ? buffer_->getWidth() : 0; }
+  int height() const { return buffer_.get() ? buffer_->getHeight() : 0; }
+  int layer_count() const {
+    return buffer_.get() ? buffer_->getLayerCount() : 0;
+  }
+  int stride() const { return buffer_.get() ? buffer_->getStride() : 0; }
   int layer_stride() const { return 0; }
-  int format() const { if (buffer_.get()) return buffer_->getPixelFormat();
-                       else return 0; }
-  int usage() const { if (buffer_.get()) return buffer_->getUsage();
-                      else return 0; }
+  int format() const { return buffer_.get() ? buffer_->getPixelFormat() : 0; }
+  int usage() const { return buffer_.get() ? buffer_->getUsage() : 0; }
 
  private:
   sp<GraphicBuffer> buffer_;