Assume a texture is unbound after deleting it
Bug #9316260

The GL specification indicates that deleting a bound texture has
the side effect of binding the default texture (name=0). This change
replaces all calls to glDeleteTextures() by Caches::deleteTexture()
to properly keep track of texture bindings.

Change-Id: Ifbc60ef433e0f9776a668dd5bd5f0adbc65a77a0
diff --git a/libs/hwui/Dither.cpp b/libs/hwui/Dither.cpp
index 4dc85e0..649a7bc 100644
--- a/libs/hwui/Dither.cpp
+++ b/libs/hwui/Dither.cpp
@@ -77,7 +77,7 @@
 
 void Dither::clear() {
     if (mInitialized) {
-        glDeleteTextures(1, &mDitherTexture);
+        mCaches->deleteTexture(mDitherTexture);
         mInitialized = false;
     }
 }