Fix Skia's impl for TextureView.getBitmap

Bug: 73392905
Test: New test added with I2d4ef440f943a50b9367976ba1444f4350071bfd

When providing a width and height, getBitmap should scale to the
destination. Add a parameter to LayerDrawable::DrawLayer for a
destination rectangle to scale to. Pass the size of the bitmap in
SkiaOpenGLPipeline::copyLayerInto down to DrawLayer. The only other
caller of DrawLayer is unaffected.

Change-Id: I7aa192181c2d15bc8fd4de2fb15c4d276b05d2ac