diff --git a/include/private/ui/LayerState.h b/include/private/ui/LayerState.h
new file mode 100644
index 0000000..b6fcd80
--- /dev/null
+++ b/include/private/ui/LayerState.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_COMPOSER_LAYER_STATE_H
+#define ANDROID_COMPOSER_LAYER_STATE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <ui/ISurfaceFlingerClient.h>
+#include <ui/Region.h>
+
+#include <private/ui/SharedState.h>
+
+namespace android {
+
+class Parcel;
+
+struct layer_state_t {
+
+    layer_state_t()
+        :   surface(0), what(0),
+            x(0), y(0), z(0), w(0), h(0),
+            alpha(0), tint(0), flags(0), mask(0),
+            reserved(0)
+    {
+        matrix.dsdx = matrix.dtdy = 1.0f;
+        matrix.dsdy = matrix.dtdx = 0.0f;
+    }
+
+    status_t    write(Parcel& output) const;
+    status_t    read(const Parcel& input);
+
+            struct matrix22_t {
+                float   dsdx;
+                float   dtdx;
+                float   dsdy;
+                float   dtdy;
+            };
+            SurfaceID       surface;
+            uint32_t        what;
+            int32_t         x;
+            int32_t         y;
+            uint32_t        z;
+            uint32_t        w;
+            uint32_t        h;
+            float           alpha;
+            uint32_t        tint;
+            uint8_t         flags;
+            uint8_t         mask;
+            uint8_t         reserved;
+            matrix22_t      matrix;
+            // non POD must be last. see write/read
+            Region          transparentRegion;
+};
+
+}; // namespace android
+
+#endif // ANDROID_COMPOSER_LAYER_STATE_H
+
diff --git a/include/private/ui/SharedState.h b/include/private/ui/SharedState.h
new file mode 100644
index 0000000..546d0ad
--- /dev/null
+++ b/include/private/ui/SharedState.h
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_UI_SHARED_STATE_H
+#define ANDROID_UI_SHARED_STATE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/threads.h>
+
+namespace android {
+
+/*
+ * These structures are shared between the composer process and its clients
+ */
+
+// ---------------------------------------------------------------------------
+
+struct surface_info_t { // 4 longs, 16 bytes
+    enum {
+        eBufferDirty    = 0x01
+    };
+    uint16_t    w;
+    uint16_t    h;
+    uint16_t    stride;
+    uint16_t    bpr;
+    uint16_t    reserved;
+    uint8_t     format;
+    uint8_t     flags;
+    ssize_t     bits_offset;
+};
+
+// ---------------------------------------------------------------------------
+
+const uint32_t NUM_LAYERS_MAX = 31;
+
+enum { // layer_cblk_t swapState
+    eIndex              = 0x00000001,
+    eFlipRequested      = 0x00000002,
+    
+    eResizeBuffer0      = 0x00000004,
+    eResizeBuffer1      = 0x00000008,    
+    eResizeRequested    = eResizeBuffer0 | eResizeBuffer1,
+    
+    eBusy               = 0x00000010,
+    eLocked             = 0x00000020,
+    eNextFlipPending    = 0x00000040,    
+    eInvalidSurface     = 0x00000080
+};
+
+enum { // layer_cblk_t flags
+    eLayerNotPosted     = 0x00000001,
+    eNoCopyBack         = 0x00000002,
+    eReserved           = 0x0000007C,
+    eBufferIndexShift   = 7,
+    eBufferIndex        = 1<<eBufferIndexShift,
+};
+
+struct flat_region_t    // 40 bytes
+{
+    int32_t     count;
+    int16_t     l;
+    int16_t     t;
+    int16_t     r;
+    int16_t     b;
+    uint16_t    runs[14];
+};
+
+struct layer_cblk_t     // (128 bytes)
+{
+    volatile    int32_t             swapState;      //  4
+    volatile    int32_t             flags;          //  4
+    volatile    int32_t             identity;       //  4
+                int32_t             reserved;       //  4
+                surface_info_t      surface[2];     // 32
+                flat_region_t       region[2];      // 80
+
+    static inline int backBuffer(uint32_t state) {
+        return ((state & eIndex) ^ ((state & eFlipRequested)>>1));
+    }
+    static inline int frontBuffer(uint32_t state) {
+        return 1 - backBuffer(state);
+    }
+};
+
+// ---------------------------------------------------------------------------
+
+struct per_client_cblk_t   // 4KB max
+{
+                Mutex           lock;
+                Condition       cv;
+                layer_cblk_t    layers[NUM_LAYERS_MAX] __attribute__((aligned(32)));
+
+    enum {
+        BLOCKING = 0x00000001,
+        INSPECT  = 0x00000002
+    };
+
+    per_client_cblk_t();
+
+    // these functions are used by the clients
+    status_t validate(size_t i) const;
+    int32_t lock_layer(size_t i, uint32_t flags);
+    uint32_t unlock_layer_and_post(size_t i);
+    void unlock_layer(size_t i);
+};
+// ---------------------------------------------------------------------------
+
+const uint32_t NUM_DISPLAY_MAX = 4;
+
+struct display_cblk_t
+{
+    uint16_t    w;
+    uint16_t    h;
+    uint8_t     format;
+    uint8_t     orientation;
+    uint8_t     reserved[2];
+    float       fps;
+    float       density;
+    float       xdpi;
+    float       ydpi;
+    uint32_t    pad[2];
+};
+
+struct surface_flinger_cblk_t   // 4KB max
+{
+    surface_flinger_cblk_t();
+    
+    uint8_t         connected;
+    uint8_t         reserved[3];
+    uint32_t        pad[7];
+ 
+    display_cblk_t  displays[NUM_DISPLAY_MAX];
+};
+
+// ---------------------------------------------------------------------------
+
+template<bool> struct CTA;
+template<> struct CTA<true> { };
+
+// compile-time assertions. just to avoid catastrophes.
+inline void compile_time_asserts() {
+    CTA<sizeof(layer_cblk_t) == 128> sizeof__layer_cblk_t__eq_128;
+    (void)sizeof__layer_cblk_t__eq_128; // we don't want a warning
+    CTA<sizeof(per_client_cblk_t) <= 4096> sizeof__per_client_cblk_t__le_4096;
+    (void)sizeof__per_client_cblk_t__le_4096;  // we don't want a warning
+    CTA<sizeof(surface_flinger_cblk_t) <= 4096> sizeof__surface_flinger_cblk_t__le_4096;
+    (void)sizeof__surface_flinger_cblk_t__le_4096;  // we don't want a warning
+}
+
+}; // namespace android
+
+#endif // ANDROID_UI_SHARED_STATE_H
+
diff --git a/include/private/ui/SurfaceFlingerSynchro.h b/include/private/ui/SurfaceFlingerSynchro.h
new file mode 100644
index 0000000..ff91b61
--- /dev/null
+++ b/include/private/ui/SurfaceFlingerSynchro.h
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#ifndef ANDROID_SURFACE_FLINGER_SYNCHRO_H
+#define ANDROID_SURFACE_FLINGER_SYNCHRO_H
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <utils/Errors.h>
+#include <utils/threads.h>
+#include <ui/ISurfaceComposer.h>
+
+namespace android {
+
+class SurfaceFlinger;
+
+class SurfaceFlingerSynchro
+{
+public:
+
+                // client constructor
+                SurfaceFlingerSynchro(const sp<ISurfaceComposer>& flinger);
+                ~SurfaceFlingerSynchro();
+    
+                // signal surfaceflinger for some work
+    status_t    signal();
+    
+private:
+    class Barrier {
+    public:
+        Barrier();
+        ~Barrier();
+        void open();
+        void close();
+        void waitAndClose();
+        status_t waitAndClose(nsecs_t timeout);
+    private:
+        enum { OPENED, CLOSED };
+        mutable     Mutex       lock;
+        mutable     Condition   cv;
+        volatile    int         state;
+    };
+
+    friend class SurfaceFlinger;
+
+                // server constructor
+                SurfaceFlingerSynchro();
+                
+    void        open();
+    
+                // wait until there is some work to do
+    status_t    wait();
+    status_t    wait(nsecs_t timeout);
+    
+    sp<ISurfaceComposer> mSurfaceComposer;
+    Barrier              mBarrier;
+};
+
+}; // namespace android
+
+#endif // ANDROID_SURFACE_FLINGER_SYNCHRO_H
+