[Tracing] Support multi-categories group list.

jasongin@ created this patch.
https://github.com/jasongin/nodejs/commit/dcc50445a364664586164f42f9250732bd372982
This patch adds the support to emit a trace event by using a comma-separated
list of categories, so that the trace event will be emitted if there is at least
one category is enabled in the categories list.

TBR=jochen@chromium.org

Review-Url: https://codereview.chromium.org/2558193002
Cr-Commit-Position: refs/heads/master@{#41567}

src/libplatform/tracing/trace-config.cc

@@ -21,8 +21,13 @@ TraceConfig* TraceConfig::CreateDefaultTraceConfig() {
 }
 
 bool TraceConfig::IsCategoryGroupEnabled(const char* category_group) const {
-  for (auto included_category : included_categories_) {
-    if (strcmp(included_category.data(), category_group) == 0) return true;
+  std::stringstream category_stream(category_group);
+  while (category_stream.good()) {
+    std::string category;
+    getline(category_stream, category, ',');
+    for (auto included_category : included_categories_) {
+      if (category == included_category) return true;
+    }
   }
   return false;
 }

test/cctest/libplatform/test-tracing.cc

@@ -25,6 +25,14 @@ TEST(TestTraceConfig) {
   CHECK_EQ(trace_config->IsCategoryGroupEnabled(
                TRACE_DISABLED_BY_DEFAULT("v8.runtime")),
            true);
+  CHECK_EQ(trace_config->IsCategoryGroupEnabled("v8,v8.cpu_profile"), true);
+  CHECK_EQ(
+      trace_config->IsCategoryGroupEnabled("v8,disabled-by-default-v8.runtime"),
+      true);
+  CHECK_EQ(trace_config->IsCategoryGroupEnabled(
+               "v8_cpu_profile,v8.cpu_profile.hires"),
+           false);
+
   delete trace_config;
 }