Rename cc::ResourceProvider::ResourceId to cc::ResourceId and move it to its own file.

cc/layers/picture_layer_impl_unittest.cc

Index: cc/layers/picture_layer_impl_unittest.cc
diff --git a/cc/layers/picture_layer_impl_unittest.cc b/cc/layers/picture_layer_impl_unittest.cc
index 2bf369684a25b210224946322a48ad6db0f6319a..75725257282d60c1134d7f594fd647ce6f84cf9c 100644
--- a/cc/layers/picture_layer_impl_unittest.cc
+++ b/cc/layers/picture_layer_impl_unittest.cc
@@ -1370,7 +1370,7 @@ TEST_F(PictureLayerImplTest, HugeMasksGetScaledDown) {
   // Mask layers have a tiling with a single tile in it.
   EXPECT_EQ(1u, active_mask->HighResTiling()->AllTilesForTesting().size());
   // The mask resource exists.
-  ResourceProvider::ResourceId mask_resource_id;
+  ResourceId mask_resource_id;
   gfx::Size mask_texture_size;
   active_mask->GetContentsResourceId(&mask_resource_id, &mask_texture_size);
   EXPECT_NE(0u, mask_resource_id);
@@ -1512,7 +1512,7 @@ TEST_F(PictureLayerImplTest, ScaledMaskLayer) {
   // Mask layers have a tiling with a single tile in it.
   EXPECT_EQ(1u, active_mask->HighResTiling()->AllTilesForTesting().size());
   // The mask resource exists.
-  ResourceProvider::ResourceId mask_resource_id;
+  ResourceId mask_resource_id;
   gfx::Size mask_texture_size;
   active_mask->GetContentsResourceId(&mask_resource_id, &mask_texture_size);
   EXPECT_NE(0u, mask_resource_id);