Add LOCAL_ prefix to non-UMA histogram macros.

This makes it harder to accidently use the wrong
macro.

Also, removes the D* variants of the macros and
associated DebugNow() function. These were rarely
used and removing them removes clutter from the
header file. Existing uses converted to be behind
NDEBUG ifdefs.

No functional changes except for a fix to the
code in content_based_thumbnailing_algorithm.cc
which was incorrectly using a ternary operator for
the histogram name (which doesn't work since the
macros cache the histogram object) and removal
of local histograms Spellcheck.SuggestTime and
Spellcheck.InitTime per groby@.

Since this is an API rename, TBR'ing downstream
owners.

BUG=311349
TBR=groby@chromium.org,zea@chromium.org,jeremy@chromium.org,reveman@chromium.org,agl@chromium.org,jam@chromium.org

Review URL: https://codereview.chromium.org/484603006

Cr-Commit-Position: refs/heads/master@{#291840}

1 files changed, 3 insertions, 3 deletions

diff --git a/sync/util/data_type_histogram_unittest.cc b/sync/util/data_type_histogram_unittest.cc
index 67b5e64..df65735 100644
--- a/sync/util/data_type_histogram_unittest.cc
+++ b/sync/util/data_type_histogram_unittest.cc
@@ -13,13 +13,13 @@ namespace {
 class DataTypeHistogramTest : public testing::Test {
 };
 
-// Create a histogram of type HISTOGRAM_COUNTS for each model type. Nothing
-// should break.
+// Create a histogram of type LOCAL_HISTOGRAM_COUNTS for each model type.
+// Nothing should break.
 TEST(DataTypeHistogramTest, BasicCount) {
   for (int i = FIRST_REAL_MODEL_TYPE; i <= LAST_REAL_MODEL_TYPE; ++i) {
     ModelType type = ModelTypeFromInt(i);
 #define PER_DATA_TYPE_MACRO(type_str) \
-    HISTOGRAM_COUNTS("Prefix" type_str "Suffix", 1);
+    LOCAL_HISTOGRAM_COUNTS("Prefix" type_str "Suffix", 1);
     SYNC_DATA_TYPE_HISTOGRAM(type);
 #undef PER_DATA_TYPE_MACRO
   }