fixes for [2474091] Saw Poor behaviour playing a video.

- fix a bug when hacking video buffers into gralloc buffers
 where the buffer size was incorrect this was causing the
 "direct-form-texture" mode to fail

- also when the above fails, make sure to revert to the
 "mdp copy mode" before going to "slow mode"

- finally disable completely the "direct-from-texture" mode
 for now. It cannot work because the allocated buffers can't
 respect the GPU constraints (alignment and such). We'll
 have to find a solution for that.
diff --git a/libs/surfaceflinger/LayerBuffer.h b/libs/surfaceflinger/LayerBuffer.h
index eb5b8eb..b176623 100644
--- a/libs/surfaceflinger/LayerBuffer.h
+++ b/libs/surfaceflinger/LayerBuffer.h
@@ -99,7 +99,8 @@
 
     class Buffer : public LightRefBase<Buffer> {
     public:
-        Buffer(const ISurface::BufferHeap& buffers, ssize_t offset);
+        Buffer(const ISurface::BufferHeap& buffers,
+                ssize_t offset, size_t bufferSize);
         inline bool supportsCopybit() const {
             return mSupportsCopybit;
         }