Automatically prepend "disabled-by-default-" to TRACE categories

Ensures that all Skia events are disabled by default in Chrome, and
eliminates redundant typing.

Bug: skia:
Change-Id: I289c5e5a01084fcf4cccf512da65a4727f4aeca2
Reviewed-on: https://skia-review.googlesource.com/26880
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
diff --git a/src/gpu/GrBufferAllocPool.cpp b/src/gpu/GrBufferAllocPool.cpp
index 3096ae5..53e0d8c 100644
--- a/src/gpu/GrBufferAllocPool.cpp
+++ b/src/gpu/GrBufferAllocPool.cpp
@@ -30,7 +30,7 @@
 
 #define UNMAP_BUFFER(block)                                                               \
 do {                                                                                      \
-    TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("skia.gpu"),                           \
+    TRACE_EVENT_INSTANT1("skia.gpu",                                                      \
                          "GrBufferAllocPool Unmapping Buffer",                            \
                          TRACE_EVENT_SCOPE_THREAD,                                        \
                          "percent_unwritten",                                             \