Determine mask UVs based on texture size

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 2e7457a49aac6600be861bf479eb244c545a3d17..de0c68bcfa0e2306a0de94f8d875d33103fc9891 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -6725,10 +6725,10 @@ class LayerTreeTestMaskLayerForSurfaceWithClippedLayer : public LayerTreeTest {
         RenderPassDrawQuad::MaterialCast(root_pass->quad_list.front());
     EXPECT_EQ(gfx::Rect(20, 10, 10, 20).ToString(),
               render_pass_quad->rect.ToString());
-    // The masked layer is 50x50, but the surface size is 10x20. So the texture
-    // coords in the mask are scaled by 10/50 and 20/50.
+    // The mask layer is 100x100, but the surface size is 10x20. So the texture
+    // coords in the mask are scaled by 10/100 and 20/100.
     // The surface is clipped to (20,10) so the mask texture coords are offset
-    // by 20/50 and 10/50
+    // by 20/100 and 10/100
     if (host_impl->settings().enable_mask_tiling) {
       PictureLayerImpl* mask_layer_impl = static_cast<PictureLayerImpl*>(
           host_impl->active_tree()->LayerById(mask_layer_id_));
@@ -6740,7 +6740,7 @@ class LayerTreeTestMaskLayerForSurfaceWithClippedLayer : public LayerTreeTest {
               .ToString(),
           render_pass_quad->mask_uv_rect.ToString());
     } else {
-      EXPECT_EQ(gfx::ScaleRect(gfx::RectF(20.f, 10.f, 10.f, 20.f), 1.f / 50.f)
+      EXPECT_EQ(gfx::ScaleRect(gfx::RectF(20.f, 10.f, 10.f, 20.f), 1.f / 100.f)
                     .ToString(),
                 render_pass_quad->mask_uv_rect.ToString());
     }
@@ -6946,7 +6946,7 @@ class LayerTreeTestMaskLayerWithDifferentBounds : public LayerTreeTest {
           EXPECT_EQ(gfx::RectF(0.f, 0.f, 50.f / 128.f, 50.f / 128.f).ToString(),
                     render_pass_quad->mask_uv_rect.ToString());
         } else {
-          EXPECT_EQ(gfx::RectF(0.f, 0.f, 1.f, 1.f).ToString(),
+          EXPECT_EQ(gfx::RectF(0.f, 0.f, 50.f / 100.f, 50.f / 100.f).ToString(),
                     render_pass_quad->mask_uv_rect.ToString());
         }
         break;
@@ -6959,7 +6959,7 @@ class LayerTreeTestMaskLayerWithDifferentBounds : public LayerTreeTest {
           EXPECT_EQ(gfx::RectF(0.f, 0.f, 50.f / 128.f, 50.f / 128.f).ToString(),
                     render_pass_quad->mask_uv_rect.ToString());
         } else {
-          EXPECT_EQ(gfx::RectF(0.f, 0.f, 1.f, 1.f).ToString(),
+          EXPECT_EQ(gfx::RectF(0.f, 0.f, 50.f / 100.f, 50.f / 100.f).ToString(),
                     render_pass_quad->mask_uv_rect.ToString());
         }
         EndTest();