Don't build trace_processor:unittests on Android

Minor follow ups to "Push cpu first in FtraceEventBundle"
- Adjust a comment
- Don't build trace_processor:unittests on Android

Change-Id: I0dc352da23d0db51b612959b50d3f2920ecae4d2
diff --git a/BUILD.gn b/BUILD.gn
index dd03eaf..b6738d7 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -115,7 +115,7 @@
       "tools/sanitizers_unittests",
     ]
   }
-  if (build_standalone) {
+  if (build_standalone && !is_android) {
     deps += [ "src/trace_processor:unittests" ]
   }
 }
diff --git a/src/trace_processor/proto_trace_parser.cc b/src/trace_processor/proto_trace_parser.cc
index a8772df..d9b251d 100644
--- a/src/trace_processor/proto_trace_parser.cc
+++ b/src/trace_processor/proto_trace_parser.cc
@@ -232,7 +232,7 @@
   constexpr auto kCpuFieldTag = MakeTagVarInt(kCpuFieldNumber);
 
   // For speed we speculate on the location and size (<128) of the cpu field.
-  // In P+ cpu is pushed as the first field.
+  // In Q+ cpu is pushed as the first field.
   // In P cpu is pushed as the 2nd last field.
   if (length > 2 && data[0] == kCpuFieldTag && data[1] < 0x80) {
     cpu = data[1];