Pass defines to MIDL compiler and define IDL UUIDs in .gn file.

The adopters of the updater project should be able to change the guids
of the COM service exposed by the updater.exe to prevent conflicts
when services are installed on the same machine. To make it easier to
deal with conflicts, we want the UUIDs to be defined outside of the .IDL.

This change allows for compile-time defines expressed in GN to be passed
to the midl.exe compiler.

Change-Id: I6764d1625fb01635c8426d3634ff6fcd7561ae27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2094711
Commit-Queue: Maciek Kumorek <makumo@microsoft.com>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#751799}

build/toolchain/win/midl.gni

@@ -32,6 +32,10 @@ import("//build/config/win/visual_studio_version.gni")
 #       Whether a .tlb file should be added to outputs. Defaults to false.
 #
 #   deps (optional)
+#
+#   defines (optional)
+#       Build time defines to be passed to midl.exe as /D parameter.
+#
 #   visibility (optional)
 
 template("midl") {
@@ -127,6 +131,12 @@ template("midl") {
       "/Oicf",
     ]
 
+    if (defined(invoker.defines)) {
+      foreach(define, invoker.defines) {
+        args += [ "/D" + define ]
+      }
+    }
+
     forward_variables_from(invoker, [ "deps" ])
   }
 

chrome/updater/server/win/BUILD.gn

@@ -6,6 +6,12 @@ import("//build/toolchain/win/midl.gni")
 
 midl("updater_idl_idl") {
   sources = [ "updater_idl.idl" ]
+  defines = [
+    "IUPDATER_IID=63B8FFB1-5314-48C9-9C57-93EC8BC6184B",
+    "UPDATER_LIB_UUID=69464FF0-D9EC-4037-A35F-8AE4358106CC",
+    "UPDATER_CLSID=158428A4-6014-4978-83BA-9FAD0DABE791",
+    "UPDATER_SERVICE_UUID=415FD747-D79E-42D7-93AC-1BA6E5FD4E93",
+  ]
 
   writes_tlb = true
 }

chrome/updater/server/win/updater_idl.idl

@@ -31,7 +31,7 @@ interface IUpdaterObserver : IUnknown {
 [
   object,
   dual,
-  uuid(63B8FFB1-5314-48C9-9C57-93EC8BC6184B),
+  uuid(IUPDATER_IID),
   helpstring("IUpdater Interface"),
   pointer_default(unique)
 ]
@@ -47,7 +47,7 @@ interface IUpdater : IUnknown {
 };
 
 [
-  uuid(69464FF0-D9EC-4037-A35F-8AE4358106CC),
+  uuid(UPDATER_LIB_UUID),
   version(1.0),
   helpstring("Omaha 4.0 Type Library")
 ]
@@ -57,7 +57,7 @@ library UpdaterLib {
   interface IUpdater;
 
   [
-    uuid(158428A4-6014-4978-83BA-9FAD0DABE791),
+    uuid(UPDATER_CLSID),
     helpstring("Updater Class")
   ]
   coclass UpdaterClass
@@ -66,7 +66,7 @@ library UpdaterLib {
   }
 
   [
-    uuid(415FD747-D79E-42D7-93AC-1BA6E5FD4E93),
+    uuid(UPDATER_SERVICE_UUID),
     helpstring("Updater Service Class")
   ]
   coclass UpdaterServiceClass