Reland - Update DevTools Tracing.Start to accept trace config as a parameter

Original CL: https://crrev.com/1765153002

Forgot to decouple some statement from DCHECK, which was actually
pointed out by Primiano before. Should be fixed now.

--------------------
original description
--------------------

This CL updates Tracing.Start to accept trace config as
a parameter when starting tracing. It is backward compatible
with the old way.

Design doc: https://goo.gl/GxQ23k
BUG=579358
TBR=primiano@chromium.org,caseq@chromium.org,simonhatch@chromium.org,petrcermak@chromium.org,pfeldman@chromium.org

Review URL: https://codereview.chromium.org/1808353002

Cr-Commit-Position: refs/heads/master@{#381892}

3 files changed, 102 insertions, 20 deletions

diff --git a/base/trace_event/trace_config.cc b/base/trace_event/trace_config.cc
index d60c081..c2c7ad7 100644
--- a/base/trace_event/trace_config.cc
+++ b/base/trace_event/trace_config.cc
@@ -105,6 +105,10 @@ TraceConfig::TraceConfig(const std::string& category_filter_string,
   InitializeFromStrings(category_filter_string, trace_options_string);
 }
 
+TraceConfig::TraceConfig(const DictionaryValue& config) {
+  InitializeFromConfigDict(config);
+}
+
 TraceConfig::TraceConfig(const std::string& config_string) {
   if (!config_string.empty())
     InitializeFromConfigString(config_string);
@@ -288,18 +292,10 @@ void TraceConfig::InitializeDefault() {
   excluded_categories_.push_back("*Test");
 }
 
-void TraceConfig::InitializeFromConfigString(const std::string& config_string) {
-  scoped_ptr<base::Value> value(base::JSONReader::Read(config_string));
-  if (!value || !value->IsType(base::Value::TYPE_DICTIONARY)) {
-    InitializeDefault();
-    return;
-  }
-  scoped_ptr<base::DictionaryValue> dict(
-        static_cast<base::DictionaryValue*>(value.release()));
-
+void TraceConfig::InitializeFromConfigDict(const DictionaryValue& dict) {
   record_mode_ = RECORD_UNTIL_FULL;
   std::string record_mode;
-  if (dict->GetString(kRecordModeParam, &record_mode)) {
+  if (dict.GetString(kRecordModeParam, &record_mode)) {
     if (record_mode == kRecordUntilFull) {
       record_mode_ = RECORD_UNTIL_FULL;
     } else if (record_mode == kRecordContinuously) {
@@ -312,42 +308,57 @@ void TraceConfig::InitializeFromConfigString(const std::string& config_string) {
   }
 
   bool enable_sampling;
-  if (!dict->GetBoolean(kEnableSamplingParam, &enable_sampling))
+  if (!dict.GetBoolean(kEnableSamplingParam, &enable_sampling))
     enable_sampling_ = false;
   else
     enable_sampling_ = enable_sampling;
 
   bool enable_systrace;
-  if (!dict->GetBoolean(kEnableSystraceParam, &enable_systrace))
+  if (!dict.GetBoolean(kEnableSystraceParam, &enable_systrace))
     enable_systrace_ = false;
   else
     enable_systrace_ = enable_systrace;
 
   bool enable_argument_filter;
-  if (!dict->GetBoolean(kEnableArgumentFilterParam, &enable_argument_filter))
+  if (!dict.GetBoolean(kEnableArgumentFilterParam, &enable_argument_filter))
     enable_argument_filter_ = false;
   else
     enable_argument_filter_ = enable_argument_filter;
 
-  base::ListValue* category_list = nullptr;
-  if (dict->GetList(kIncludedCategoriesParam, &category_list))
+  const base::ListValue* category_list = nullptr;
+  if (dict.GetList(kIncludedCategoriesParam, &category_list))
     SetCategoriesFromIncludedList(*category_list);
-  if (dict->GetList(kExcludedCategoriesParam, &category_list))
+  if (dict.GetList(kExcludedCategoriesParam, &category_list))
     SetCategoriesFromExcludedList(*category_list);
-  if (dict->GetList(kSyntheticDelaysParam, &category_list))
+  if (dict.GetList(kSyntheticDelaysParam, &category_list))
     SetSyntheticDelaysFromList(*category_list);
 
   if (IsCategoryEnabled(MemoryDumpManager::kTraceCategory)) {
     // If dump triggers not set, the client is using the legacy with just
     // category enabled. So, use the default periodic dump config.
-    base::DictionaryValue* memory_dump_config = nullptr;
-    if (dict->GetDictionary(kMemoryDumpConfigParam, &memory_dump_config))
+    const base::DictionaryValue* memory_dump_config = nullptr;
+    if (dict.GetDictionary(kMemoryDumpConfigParam, &memory_dump_config))
       SetMemoryDumpConfig(*memory_dump_config);
     else
       SetDefaultMemoryDumpConfig();
   }
 }
 
+void TraceConfig::InitializeFromConfigString(const std::string& config_string) {
+  scoped_ptr<Value> value(JSONReader::Read(config_string));
+  if (!value)
+    return InitializeDefault();
+
+  const DictionaryValue* dict = nullptr;
+  bool is_dict = value->GetAsDictionary(&dict);
+
+  if (!is_dict)
+    return InitializeDefault();
+
+  DCHECK(dict);
+  InitializeFromConfigDict(*dict);
+}
+
 void TraceConfig::InitializeFromStrings(
     const std::string& category_filter_string,
     const std::string& trace_options_string) {
diff --git a/base/trace_event/trace_config.h b/base/trace_event/trace_config.h
index 81b7d51..75e001b 100644
--- a/base/trace_event/trace_config.h
+++ b/base/trace_event/trace_config.h
@@ -130,6 +130,10 @@ class BASE_EXPORT TraceConfig {
   // disabled-by-default-memory-infra category is enabled.
   explicit TraceConfig(const std::string& config_string);
 
+  // Functionally identical to the above, but takes a parsed dictionary as input
+  // instead of its JSON serialization.
+  explicit TraceConfig(const DictionaryValue& config);
+
   TraceConfig(const TraceConfig& tc);
 
   ~TraceConfig();
@@ -190,7 +194,10 @@ class BASE_EXPORT TraceConfig {
   // in the suffix 'Debug' or 'Test'.
   void InitializeDefault();
 
-  // Initialize from the config string
+  // Initialize from a config dictionary.
+  void InitializeFromConfigDict(const DictionaryValue& dict);
+
+  // Initialize from a config string.
   void InitializeFromConfigString(const std::string& config_string);
 
   // Initialize from category filter and trace options strings
diff --git a/base/trace_event/trace_config_unittest.cc b/base/trace_event/trace_config_unittest.cc
index bd37880..1b49fdc 100644
--- a/base/trace_event/trace_config_unittest.cc
+++ b/base/trace_event/trace_config_unittest.cc
@@ -4,6 +4,7 @@
 
 #include <stddef.h>
 
+#include "base/json/json_reader.h"
 #include "base/macros.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/trace_config.h"
@@ -23,6 +24,27 @@ const char kDefaultTraceConfigString[] =
     "\"excluded_categories\":[\"*Debug\",\"*Test\"],"
     "\"record_mode\":\"record-until-full\""
   "}";
+
+const char kCustomTraceConfigString[] =
+  "{"
+    "\"enable_argument_filter\":true,"
+    "\"enable_sampling\":true,"
+    "\"enable_systrace\":true,"
+    "\"excluded_categories\":[\"excluded\",\"exc_pattern*\"],"
+    "\"included_categories\":[\"included\","
+                            "\"inc_pattern*\","
+                            "\"disabled-by-default-cc\","
+                            "\"disabled-by-default-memory-infra\"],"
+    "\"memory_dump_config\":{"
+      "\"triggers\":["
+        "{\"mode\":\"light\",\"periodic_interval_ms\":50},"
+        "{\"mode\":\"detailed\",\"periodic_interval_ms\":1000}"
+      "]"
+    "},"
+    "\"record_mode\":\"record-continuously\","
+    "\"synthetic_delays\":[\"test.Delay1;16\",\"test.Delay2;32\"]"
+  "}";
+
 }  // namespace
 
 TEST(TraceConfigTest, TraceConfigFromValidLegacyFormat) {
@@ -259,6 +281,48 @@ TEST(TraceConfigTest, ConstructDefaultTraceConfig) {
   EXPECT_FALSE(tc.IsCategoryGroupEnabled("CategoryDebug,CategoryTest"));
 }
 
+TEST(TraceConfigTest, TraceConfigFromDict) {
+  // Passing in empty dictionary will not result in default trace config.
+  DictionaryValue dict;
+  TraceConfig tc(dict);
+  EXPECT_STRNE(kDefaultTraceConfigString, tc.ToString().c_str());
+  EXPECT_EQ(RECORD_UNTIL_FULL, tc.GetTraceRecordMode());
+  EXPECT_FALSE(tc.IsSamplingEnabled());
+  EXPECT_FALSE(tc.IsSystraceEnabled());
+  EXPECT_FALSE(tc.IsArgumentFilterEnabled());
+  EXPECT_STREQ("", tc.ToCategoryFilterString().c_str());
+
+  scoped_ptr<Value> default_value(JSONReader::Read(kDefaultTraceConfigString));
+  DCHECK(default_value);
+  const DictionaryValue* default_dict = nullptr;
+  bool is_dict = default_value->GetAsDictionary(&default_dict);
+  DCHECK(is_dict);
+  TraceConfig default_tc(*default_dict);
+  EXPECT_STREQ(kDefaultTraceConfigString, default_tc.ToString().c_str());
+  EXPECT_EQ(RECORD_UNTIL_FULL, default_tc.GetTraceRecordMode());
+  EXPECT_FALSE(default_tc.IsSamplingEnabled());
+  EXPECT_FALSE(default_tc.IsSystraceEnabled());
+  EXPECT_FALSE(default_tc.IsArgumentFilterEnabled());
+  EXPECT_STREQ("-*Debug,-*Test", default_tc.ToCategoryFilterString().c_str());
+
+  scoped_ptr<Value> custom_value(JSONReader::Read(kCustomTraceConfigString));
+  DCHECK(custom_value);
+  const DictionaryValue* custom_dict = nullptr;
+  is_dict = custom_value->GetAsDictionary(&custom_dict);
+  DCHECK(is_dict);
+  TraceConfig custom_tc(*custom_dict);
+  EXPECT_STREQ(kCustomTraceConfigString, custom_tc.ToString().c_str());
+  EXPECT_EQ(RECORD_CONTINUOUSLY, custom_tc.GetTraceRecordMode());
+  EXPECT_TRUE(custom_tc.IsSamplingEnabled());
+  EXPECT_TRUE(custom_tc.IsSystraceEnabled());
+  EXPECT_TRUE(custom_tc.IsArgumentFilterEnabled());
+  EXPECT_STREQ("included,inc_pattern*,"
+               "disabled-by-default-cc,disabled-by-default-memory-infra,"
+               "-excluded,-exc_pattern*,"
+               "DELAY(test.Delay1;16),DELAY(test.Delay2;32)",
+               custom_tc.ToCategoryFilterString().c_str());
+}
+
 TEST(TraceConfigTest, TraceConfigFromValidString) {
   // Using some non-empty config string.
   const char config_string[] =