Second reland: Introduce mojo interface for collecting StackSamplingProfiler data

base/profiler/stack_sampling_profiler.cc

 // Copyright 2015 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.
 
 #include "base/profiler/stack_sampling_profiler.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 83 matching lines @@
 StackSamplingProfiler::Module::~Module() {}
 
 // StackSamplingProfiler::Frame -----------------------------------------------
 
 StackSamplingProfiler::Frame::Frame(uintptr_t instruction_pointer,
                                     size_t module_index)
     : instruction_pointer(instruction_pointer), module_index(module_index) {}
 
 StackSamplingProfiler::Frame::~Frame() {}
 
-StackSamplingProfiler::Frame::Frame() {}
+StackSamplingProfiler::Frame::Frame()
+    : instruction_pointer(0), module_index(kUnknownModuleIndex) {
+}
 
 // StackSamplingProfiler::CallStackProfile ------------------------------------
 
 StackSamplingProfiler::CallStackProfile::CallStackProfile() {}
 
 StackSamplingProfiler::CallStackProfile::CallStackProfile(
     const CallStackProfile& other) = default;
 
 StackSamplingProfiler::CallStackProfile::~CallStackProfile() {}
 
@@ skipping 153 matching lines @@
     sampling_thread_.reset();
 }
 
 void StackSamplingProfiler::Stop() {
   if (sampling_thread_)
     sampling_thread_->Stop();
 }
 
 // StackSamplingProfiler::Frame global functions ------------------------------
 
+bool operator==(const StackSamplingProfiler::Module& a,
+                const StackSamplingProfiler::Module& b) {
+  return a.base_address == b.base_address && a.id == b.id &&
+      a.filename == b.filename;
+}
+
 bool operator==(const StackSamplingProfiler::Frame &a,
                 const StackSamplingProfiler::Frame &b) {
   return a.instruction_pointer == b.instruction_pointer &&
       a.module_index == b.module_index;
 }
 
 bool operator<(const StackSamplingProfiler::Frame &a,
                const StackSamplingProfiler::Frame &b) {
   return (a.module_index < b.module_index) ||
       (a.module_index == b.module_index &&
        a.instruction_pointer < b.instruction_pointer);
 }
 
 }  // namespace base