Move STATIC_HISTOGRAM_POINTER_GROUP into histogram_macros.h.

ui/events/event.cc

Index: ui/events/event.cc
diff --git a/ui/events/event.cc b/ui/events/event.cc
index dc212a5faa902d6c09284c8a24d7cea4a1a61ed9..f17899623609c16403af63fadcd550aef738e08c 100644
--- a/ui/events/event.cc
+++ b/ui/events/event.cc
@@ -44,39 +44,6 @@
 #include "ui/events/keycodes/platform_key_map_win.h"
 #endif
 
-// Support a collection of histograms, perhaps one for each entry in an
-// enumeration. This macro manages a block of pointers, adding to a specific
-// one by its index.
-//
-// A typical instantiation looks something like this:
-//  STATIC_HISTOGRAM_POINTER_GROUP(
-//      GetHistogramNameForIndex(histogram_index),
-//      histogram_index, MAXIMUM_HISTOGRAM_INDEX, Add(some_delta),
-//      base::Histogram::FactoryGet(
-//          GetHistogramNameForType(histogram_index),
-//          MINIMUM_SAMPLE, MAXIMUM_SAMPLE, BUCKET_COUNT,
-//          base::HistogramBase::kUmaTargetedHistogramFlag));
-//
-// Though it seems inefficient to generate the name twice, the first
-// instance will be used only for DCHECK builds and the second will
-// execute only during the first access to the given index, after which
-// the pointer is cached and the name never needed again.
-//
-// This is defined in this way so that it can be moved unchanged into
-// base/metrics/histogram_macros.h if it is useful in other files.
-#define STATIC_HISTOGRAM_POINTER_GROUP(constant_histogram_name, index,        \
-                                       constant_maximum,                      \
-                                       histogram_add_method_invocation,       \
-                                       histogram_factory_get_invocation)      \
-  do {                                                                        \
-    static base::subtle::AtomicWord atomic_histograms[constant_maximum];      \
-    DCHECK_LE(0, index);                                                      \
-    DCHECK_LT(index, constant_maximum);                                       \
-    HISTOGRAM_POINTER_USE(&atomic_histograms[index], constant_histogram_name, \
-                          histogram_add_method_invocation,                    \
-                          histogram_factory_get_invocation);                  \
-  } while (0)
-
 namespace {
 
 std::string EventTypeName(ui::EventType type) {