arc: enable Android tracing in verified-boot mode

components/arc/trace/arc_trace_bridge.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_ARC_TRACE_ARC_TRACE_BRIDGE_H_
+#define COMPONENTS_ARC_TRACE_ARC_TRACE_BRIDGE_H_
+
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/thread_checker.h"
+#include "base/trace_event/trace_event.h"
+#include "components/arc/arc_bridge_service.h"

[Yusuke Sato, 2016/10/12 05:58:14]

nit: is this #include necessary? 

 namespace arc {

 class ArcBridgeService;

seems sufficient.

[shunhsingou, 2016/12/22 04:04:35]

Done.

+#include "components/arc/arc_service.h"
+#include "components/arc/instance_holder.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace arc {
+
+// This class provides the interface to trigger tracing in the container.
+class ArcTraceBridge : public ArcService,
+                       public InstanceHolder<mojom::TraceInstance>::Observer,
+                       public mojom::TraceHost {

[Yusuke Sato, 2016/10/12 05:58:13]

Not sure if it makes sense to implement an empty host. remove?

[shunhsingou, 2016/12/22 04:04:35]

Removed

+ public:
+  // Gets the singleton of this class.
+  static ArcTraceBridge* Get();
+
+  explicit ArcTraceBridge(ArcBridgeService* bridge_service);
+  ~ArcTraceBridge() override;
+
+  // Callback when the bridge is ready.

[Yusuke Sato, 2016/10/12 05:58:14]

// InstanceHolder<mojom::TraceInstance>::Observer overrides:

?

[shunhsingou, 2016/12/22 04:04:35]

Done.

+  void OnInstanceReady() override;
+
+  // Starts tracing in the container.
+  void StartTracing(const base::trace_event::TraceConfig& trace_config);
+
+  // Stops tracing in the container.
+  void StopTracing();
+
+ private:
+  struct Category {
+    // The name used by Android to trigger tracing.
+    const std::string name;
+    // The full name shown in the tracing UI in chrome://tracing.
+    const std::string full_name;
+
+    Category(const std::string& name, const std::string& full_name)

[Luis Héctor Chávez, 2016/10/12 17:12:40]

Can you use the uniform initialization syntax to avoid this explicit
constructor?

Category c{"name", "full_name"};

[shunhsingou, 2016/12/22 04:04:35]

Done.

+        : name(name), full_name(full_name) {}
+  };
+  mojo::Binding<mojom::TraceHost> binding_;

[Yusuke Sato, 2016/10/12 05:58:14]

same, remove?

[shunhsingou, 2016/12/22 04:04:35]

Done.

+
+  base::WeakPtrFactory<ArcTraceBridge> weak_ptr_factory_;

[Yusuke Sato, 2016/10/27 04:11:24]

weak_ptr_factory_ must be the last member variable of the class (so that
weak_ptr_factory_ is destructed before other member variables in this class
are.)

Can you run git cl try once you finish reorganizing the CL? Clang Linux builder
should have been able to catch this.

[shunhsingou, 2016/12/22 04:04:35]

Done.

+
+  base::ThreadChecker thread_checker_;
+
+  // List of available categories name. Each item is a pair of string. The

[Luis Héctor Chávez, 2016/10/12 17:12:40]

This comment is now out of date.

[shunhsingou, 2016/12/22 04:04:35]

Done.

+  // first string is the category name, and the second string is the full name
+  // shown in the trace menu UI.
+  std::vector<Category> categories_;

[Yusuke Sato, 2016/10/27 04:11:24]

This does not seem to follow the class formatting rule.

 private:
   // private member functions here...

   // private member variables here...

   DISALLOW_COPY_AND_ASSIGN(...);
 };

https://google.github.io/styleguide/cppguide.html#Class_Format

[shunhsingou, 2016/12/22 04:04:35]

Done.

+
+  // Query the available categories for tracing.
+  void QueryAvailableCategories();
+
+  // Callback for QueryAvailableCategories.
+  void OnCategoriesReady(mojo::Array<mojo::String> categories);
+
+  // Callback for StartTracing.
+  void OnTraceStart(bool success);
+
+  // Callback for StopTracing.
+  void OnTraceStop(bool success);
+
+  DISALLOW_COPY_AND_ASSIGN(ArcTraceBridge);
+};
+
+}  // namespace arc
+
+#endif  // COMPONENTS_ARC_TRACE_ARC_TRACE_BRIDGE_H_