SurfaceFlinger: Fix PTS on stale buffers

SurfaceFlinger's (Layer's) shadow copy of the BufferQueue queue was
getting out of sync for a few reasons. This change fixes these by
doing the following:

- Adds a check to re-synchronize the shadow copy every time we
  successfully acquire a buffer by first dropping stale buffers before
  removing the current buffer.
- Avoids trying to perform updates for buffers which have been rejected
  (for incorrect dimensions) by SurfaceFlinger.
- Adds IGraphicBufferConsumer::setShadowQueueSize, which allows the
  consumer to notify the BufferQueue that it is maintaining a shadow
  copy of the queue and prevents it from dropping so many buffers
  during acquireBuffer that it ends up returning a buffer for which the
  consumer has not yet received an onFrameAvailable call.

Bug: 20096136
Change-Id: I78d0738428005fc19b3be85cc8f1db498043612f
(cherry picked from commit 2e36f2283f48ab764b496490c73a132acf21df3a)
diff --git a/services/surfaceflinger/SurfaceFlingerConsumer.h b/services/surfaceflinger/SurfaceFlingerConsumer.h
index 1aaba18..a90a8b9 100644
--- a/services/surfaceflinger/SurfaceFlingerConsumer.h
+++ b/services/surfaceflinger/SurfaceFlingerConsumer.h
@@ -28,6 +28,8 @@
  */
 class SurfaceFlingerConsumer : public GLConsumer {
 public:
+    static const status_t BUFFER_REJECTED = UNKNOWN_ERROR + 8;
+
     struct ContentsChangedListener: public FrameAvailableListener {
         virtual void onSidebandStreamChanged() = 0;
     };
@@ -68,6 +70,9 @@
 
     sp<NativeHandle> getSidebandStream() const;
 
+    // See IGraphicBufferConsumer::setShadowQueueSize
+    void setShadowQueueSize(size_t size);
+
     nsecs_t computeExpectedPresent(const DispSync& dispSync);
 
 private: