Add debug mode to measure performance.

Change-Id: I9d4c84034dc200b99c8266165942a7cdbcb5c0c5
diff --git a/libs/hwui/FboCache.h b/libs/hwui/FboCache.h
new file mode 100644
index 0000000..66f66ea
--- /dev/null
+++ b/libs/hwui/FboCache.h
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2010 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_FBO_CACHE_H
+#define ANDROID_UI_FBO_CACHE_H
+
+#include <GLES2/gl2.h>
+
+#include <utils/SortedVector.h>
+
+#include "GenerationCache.h"
+
+namespace android {
+namespace uirenderer {
+
+///////////////////////////////////////////////////////////////////////////////
+// Cache
+///////////////////////////////////////////////////////////////////////////////
+
+class FboCache {
+public:
+    FboCache();
+    ~FboCache();
+
+    /**
+     * Returns an FBO from the cache. If no FBO is available, a new one
+     * is created. If creating a new FBO fails, 0 is returned.
+     *
+     * When an FBO is obtained from the cache, it is removed and the
+     * total number of FBOs available in the cache decreases.
+     *
+     * @return The name of the FBO, or 0 if no FBO can be obtained.
+     */
+    GLuint get();
+
+    /**
+     * Adds the specified FBO to the cache.
+     *
+     * @param fbo The FBO to add to the cache.
+     *
+     * @return True if the FBO was added, false otherwise.
+     */
+    bool put(GLuint fbo);
+
+    /**
+     * Clears the cache. This causes all FBOs to be deleted.
+     */
+    void clear();
+
+    /**
+     * Returns the current size of the cache.
+     */
+    uint32_t getSize();
+
+    /**
+     * Returns the maximum number of FBOs that the cache can hold.
+     */
+    uint32_t getMaxSize();
+
+private:
+    SortedVector<GLuint> mCache;
+    uint32_t mMaxSize;
+}; // class FboCache
+
+}; // namespace uirenderer
+}; // namespace android
+
+#endif // ANDROID_UI_FBO_CACHE_H