Revert "Wire up mojo tracing (#3047)"

This patch depends on another patch that hasn't landed yet.

This reverts commit 960da66f.

content_handler/BUILD.gn

@@ -36,7 +36,6 @@ executable("content_handler") {
     "//lib/ftl",
     "//lib/mtl",
     "//lib/zip",
-    "//mojo/public/c",
     "//mojo/public/cpp/application",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/system",
@@ -44,7 +43,6 @@ executable("content_handler") {
     "//mojo/services/asset_bundle/interfaces",
     "//mojo/services/content_handler/interfaces",
     "//mojo/services/framebuffer/interfaces",
-    "//mojo/services/tracing/cpp",
     "//mojo/system",
     "//third_party/skia",
 

content_handler/main.cc

@@ -21,7 +21,6 @@
 #include "mojo/public/cpp/application/run_application.h"
 #include "mojo/public/cpp/application/service_provider_impl.h"
 #include "mojo/services/content_handler/interfaces/content_handler.mojom.h"
-#include "mojo/services/tracing/cpp/tracing_client.h"
 
 namespace flutter_content_handler {
 namespace {
@@ -34,10 +33,8 @@ class App : public mojo::ApplicationImplBase {
  public:
   App() {}
   ~App() override {
-    if (initialized_) {
+    if (initialized_)
       StopThreads();
-      mojo::tracing::DestroyTracer();
-    }
   }
 
   // Overridden from ApplicationDelegate:
@@ -45,10 +42,6 @@ class App : public mojo::ApplicationImplBase {
     FTL_DCHECK(!initialized_);
     initialized_ = true;
 
-    tracing::TraceProviderRegistryPtr registry;
-    ConnectToService(shell(), "mojo:tracing", GetProxy(&registry));
-    mojo::tracing::InitializeTracer(std::move(registry));
-
     ftl::RefPtr<ftl::TaskRunner> gpu_task_runner;
     gpu_thread_ = mtl::CreateThread(&gpu_task_runner);
 

glue/BUILD.gn

@@ -29,10 +29,6 @@ source_set("glue") {
     deps += [
       "//lib/mtl",
     ]
-
-    public_deps = [
-      "//mojo/services/tracing/cpp",
-    ]
   } else {
     sources += [
       "drain_data_pipe_job_base.cc",

glue/trace_event.h

@@ -3,7 +3,13 @@
 // found in the LICENSE file.
 
 #if defined(__Fuchsia__)
-#include "mojo/services/tracing/cpp/macros.h"
+#define TRACE_EVENT0(a, b)
+#define TRACE_EVENT1(a, b, c, d)
+#define TRACE_EVENT2(a, b, c, d, e, f)
+#define TRACE_EVENT_ASYNC_BEGIN0(a, b, c)
+#define TRACE_EVENT_ASYNC_END0(a, b, c)
+#define TRACE_EVENT_ASYNC_BEGIN1(a, b, c, d, e)
+#define TRACE_EVENT_ASYNC_END1(a, b, c, d, e)
 #else
 #include "base/trace_event/trace_event.h"
 #endif  // defined(__Fuchsia__)