Add inline directives to com_init_util.h

This is required otherwise the second include in any component will
trigger multiply defined symbol errors.

BUG=708303

Change-Id: I857cb001f3310a4c35e24768e0fbbd25d6ec22a3
Reviewed-on: https://chromium-review.googlesource.com/531802Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#478773}

base/win/com_init_util.h

@@ -30,8 +30,8 @@ BASE_EXPORT void AssertComInitialized();
 BASE_EXPORT void AssertComApartmentType(ComApartmentType apartment_type);
 
 #else   // DCHECK_IS_ON()
-void AssertComInitialized() {}
-void AssertComApartmentType(ComApartmentType apartment_type) {}
+inline void AssertComInitialized() {}
+inline void AssertComApartmentType(ComApartmentType apartment_type) {}
 #endif  // DCHECK_IS_ON()
 
 }  // namespace win