Allow binding multiple textures to one DC Layer overlay.

Modify ScheduleDCLayers command to take an array of textures.  This will
allow using NV12 shared-memory GpuMemoryBuffers, which will have
separate Y and UV GLImages.

BUG=716286
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2849743002
Cr-Commit-Position: refs/heads/master@{#469468}
diff --git a/ui/gl/dc_renderer_layer_params.h b/ui/gl/dc_renderer_layer_params.h
index c1ac631..933bf02 100644
--- a/ui/gl/dc_renderer_layer_params.h
+++ b/ui/gl/dc_renderer_layer_params.h
@@ -26,7 +26,7 @@
                         const gfx::Rect clip_rect,
                         int z_order,
                         const gfx::Transform& transform,
-                        gl::GLImage* image,
+                        std::vector<scoped_refptr<gl::GLImage>> image,
                         const gfx::RectF& contents_rect,
                         const gfx::Rect& rect,
                         unsigned background_color,
@@ -40,7 +40,7 @@
   const gfx::Rect clip_rect;
   int z_order;
   const gfx::Transform transform;
-  scoped_refptr<gl::GLImage> image;
+  std::vector<scoped_refptr<gl::GLImage>> image;
   const gfx::RectF contents_rect;
   const gfx::Rect rect;
   unsigned background_color;