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

cc/trees/layer_tree_host_unittest_context.cc

Index: cc/trees/layer_tree_host_unittest_context.cc
diff --git a/cc/trees/layer_tree_host_unittest_context.cc b/cc/trees/layer_tree_host_unittest_context.cc
index a2f06113f039c3f210bce2135519ad7d6fd8ffbf..670ae8a14e66af766b1bd2e81511828fc58f17fb 100644
--- a/cc/trees/layer_tree_host_unittest_context.cc
+++ b/cc/trees/layer_tree_host_unittest_context.cc
@@ -1004,10 +1004,9 @@ class LayerTreeHostContextTestDontUseLostResources
     delegated_frame_provider_ = new DelegatedFrameProvider(
         delegated_resource_collection_.get(), frame_data.Pass());
 
-    ResourceProvider::ResourceId resource =
-        child_resource_provider_->CreateResource(
-            gfx::Size(4, 4), GL_CLAMP_TO_EDGE,
-            ResourceProvider::TEXTURE_HINT_IMMUTABLE, RGBA_8888);
+    ResourceId resource = child_resource_provider_->CreateResource(
+        gfx::Size(4, 4), GL_CLAMP_TO_EDGE,
+        ResourceProvider::TEXTURE_HINT_IMMUTABLE, RGBA_8888);
     ResourceProvider::ScopedWriteLockGL lock(child_resource_provider_.get(),
                                              resource);