base: don't enable DCHECKs in SDK builds

Until now DCHECKs were linked to the NDEBUG
symbols. This CL restricts this to: (1) standalone;
(2) chromium-tree; (3) android-tree builds.
In all other cases (in particular, for SDK/amalgamated
builds) DCHECKs are off by default, regardless of NDEBUG.
The old behavior turned out to be problematic for amalgamated
SDK users for two reasons:
1. Some of them reportedly build perfetto.cc once as
   a static library and then build perfetto.h as part
   of various .so(s). The NDEBUG flag might not match
   in all cases.
2. In general when projects that embed perfetto build in
   debug mode, they likely want to debug their own code,
   not perfetto's.

Bug: 197340286
Change-Id: Idcc94b300715c88fb578b679fb1d54f354c54adb
diff --git a/CHANGELOG b/CHANGELOG
index 4fc0ced..51843f5 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -7,7 +7,8 @@
   UI:
     *
   SDK:
-    *
+    * Changed DCHECK and DLOGs to be always disabled in SDK builds, regardless
+      of NDEBUG.
 
 
 v19.0 - 2021-09-02: