Update HWUI to store its own SkBitmap objects

This enables us to...

1) simplify the lifecycle/ownership between Java and HWUI
2) remove DisplayListRenderer::drawBitmapData and associated logic
3) track pixel lifecycle using standard SkPixelRef refcounting
4) Remove uncessary calls to ref/unref the bitmap's pixels and colorTable

Change-Id: I3c95078da20995444f6388a029414280fd654318
diff --git a/libs/hwui/TextureCache.h b/libs/hwui/TextureCache.h
index 0e33e4c..b97d92d 100644
--- a/libs/hwui/TextureCache.h
+++ b/libs/hwui/TextureCache.h
@@ -88,10 +88,10 @@
     Texture* getTransient(const SkBitmap* bitmap);
 
     /**
-     * Removes the texture associated with the specified bitmap. This is meant
+     * Removes the texture associated with the specified pixelRef. This is meant
      * to be called from threads that are not the EGL context thread.
      */
-    void releaseTexture(const SkBitmap* bitmap);
+    ANDROID_API void releaseTexture(uint32_t pixelRefStableID);
     /**
      * Process deferred removals.
      */