Allow task pools to reason about transparency.

cc/test/fake_tile_manager.cc

Index: cc/test/fake_tile_manager.cc
diff --git a/cc/test/fake_tile_manager.cc b/cc/test/fake_tile_manager.cc
index 862b1c266e8565d67787a6a0e51b5398342a45a5..36e218c0fdf84db54c8166c36d3c6fc9968e0182 100644
--- a/cc/test/fake_tile_manager.cc
+++ b/cc/test/fake_tile_manager.cc
@@ -45,9 +45,12 @@ class FakeTileTaskRunnerImpl : public TileTaskRunner, public TileTaskClient {
     }
     completed_tasks_.clear();
   }
-  ResourceFormat GetResourceFormat() const override { return RGBA_8888; }
-  bool GetResourceRequiresSwizzle() const override {
-    return !PlatformColor::SameComponentOrder(GetResourceFormat());
+  ResourceFormat GetResourceFormat(bool must_support_alpha) const override {
+    return RGBA_8888;
+  }
+  bool GetResourceRequiresSwizzle(bool must_support_alpha) const override {
+    return !PlatformColor::SameComponentOrder(
+        GetResourceFormat(must_support_alpha));
   }
 
   // Overridden from TileTaskClient: