Merge "Swap contexts when unmapping ExternalTextures" into sc-dev

        iter->second--;

        // Swap contexts if needed prior to deleting this buffer

        // See Issue 1 of

        // https://www.khronos.org/registry/EGL/extensions/EXT/EGL_EXT_protected_content.txt: even

        // when a protected context and an unprotected context are part of the same share group,

        // protected surfaces may not be accessed by an unprotected context, implying that protected

        // surfaces may only be freed when a protected context is active.

        const bool inProtected = mInProtectedContext;

        useProtectedContext(buffer->getUsage() & GRALLOC_USAGE_PROTECTED);

        if (iter->second == 0) {

            mTextureCache.erase(buffer->getId());

            mGraphicBufferExternalRefs.erase(buffer->getId());

        }

        // Swap back to the previous context so that cached values of isProtected in SurfaceFlinger

        // are up-to-date.

        if (inProtected != mInProtectedContext) {

            useProtectedContext(inProtected);

        }

    }

}