Revert of [profiler] Update cpu profile tracing format. (patchset #2 id:20001...

Revert of [profiler] Update cpu profile tracing format. (patchset #2 id:20001 of https://chromiumcodereview.appspot.com/2425093002/ )

Reason for revert:
Breaks
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/10805

See also:
https://github.com/v8/v8/wiki/Blink-layout-tests

Original issue's description:
> [profiler] Update cpu profile tracing format.
>
> Encapsulate nodes and samples into cpuProfile object.
>
> BUG=chromium:406277

TBR=caseq@chromium.org,lpy@chromium.org,yangguo@chromium.org,alph@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:406277

Review-Url: https://chromiumcodereview.appspot.com/2432373004
Cr-Commit-Position: refs/heads/master@{#40452}

src/profiler/profile-generator.cc

@@ -412,7 +412,7 @@ CpuProfile::CpuProfile(CpuProfiler* profiler, const char* title,
   value->SetDouble("startTime",
                    (start_time_ - base::TimeTicks()).InMicroseconds());
   TRACE_EVENT_SAMPLE_WITH_ID1(TRACE_DISABLED_BY_DEFAULT("v8.cpu_profiler"),
-                              "Profile", this, "data", std::move(value));
+                              "CpuProfile", this, "data", std::move(value));
 }
 
 void CpuProfile::AddPath(base::TimeTicks timestamp,
@@ -466,8 +466,6 @@ void CpuProfile::StreamPendingTraceEvents() {
   if (pending_nodes.empty() && !samples_.length()) return;
   auto value = TracedValue::Create();
 
-  if (!pending_nodes.empty() || streaming_next_sample_ != samples_.length()) {
-    value->BeginDictionary("cpuProfile");
   if (!pending_nodes.empty()) {
     value->BeginArray("nodes");
     for (auto node : pending_nodes) {
@@ -477,16 +475,13 @@ void CpuProfile::StreamPendingTraceEvents() {
     }
     value->EndArray();
   }
+
   if (streaming_next_sample_ != samples_.length()) {
     value->BeginArray("samples");
     for (int i = streaming_next_sample_; i < samples_.length(); ++i) {
       value->AppendInteger(samples_[i]->id());
     }
     value->EndArray();
-    }
-    value->EndDictionary();
-  }
-  if (streaming_next_sample_ != samples_.length()) {
     value->BeginArray("timeDeltas");
     base::TimeTicks lastTimestamp =
         streaming_next_sample_ ? timestamps_[streaming_next_sample_ - 1]
@@ -502,7 +497,8 @@ void CpuProfile::StreamPendingTraceEvents() {
   }
 
   TRACE_EVENT_SAMPLE_WITH_ID1(TRACE_DISABLED_BY_DEFAULT("v8.cpu_profiler"),
-                              "ProfileChunk", this, "data", std::move(value));
+                              "CpuProfileChunk", this, "data",
+                              std::move(value));
 }
 
 void CpuProfile::FinishProfile() {
@@ -511,7 +507,8 @@ void CpuProfile::FinishProfile() {
   auto value = TracedValue::Create();
   value->SetDouble("endTime", (end_time_ - base::TimeTicks()).InMicroseconds());
   TRACE_EVENT_SAMPLE_WITH_ID1(TRACE_DISABLED_BY_DEFAULT("v8.cpu_profiler"),
-                              "ProfileChunk", this, "data", std::move(value));
+                              "CpuProfileChunk", this, "data",
+                              std::move(value));
 }
 
 void CpuProfile::Print() {

test/cctest/test-cpu-profiler.cc

@@ -2111,8 +2111,8 @@ namespace {
 class CpuProfileEventChecker : public v8::platform::tracing::TraceWriter {
  public:
   void AppendTraceEvent(TraceObject* trace_event) override {
-    if (trace_event->name() != std::string("Profile") &&
-        trace_event->name() != std::string("ProfileChunk"))
+    if (trace_event->name() != std::string("CpuProfile") &&
+        trace_event->name() != std::string("CpuProfileChunk"))
       return;
     CHECK(!profile_id_ || trace_event->id() == profile_id_);
     CHECK_EQ(1, trace_event->num_args());