Add trace code to track all posted tasks in message_loop and WorkerThreads (non-official builds only).

It's very helpful to understand what chrome is doing at runtime. Sometimes a thread in chrome does something expensive that causes a frame hitch. With this change, any expensive task will show up clearly in traces, with the file/function of where the task was posted.

TEST=go to about:tracing, run a trace and notice that all tasks are traced.

Review URL: http://codereview.chromium.org/7778033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@103740 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 17 insertions, 2 deletions

diff --git a/base/threading/worker_pool_posix.cc b/base/threading/worker_pool_posix.cc
index c3a382c..3a4408c 100644
--- a/base/threading/worker_pool_posix.cc
+++ b/base/threading/worker_pool_posix.cc
@@ -5,6 +5,7 @@
 #include "base/threading/worker_pool_posix.h"
 
 #include "base/bind.h"
+#include "base/debug/trace_event.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
@@ -83,6 +84,9 @@ void WorkerThread::ThreadMain() {
     PosixDynamicThreadPool::PendingTask pending_task = pool_->WaitForTask();
     if (pending_task.task.is_null())
       break;
+    UNSHIPPED_TRACE_EVENT2("task", "WorkerThread::ThreadMain::Run",
+        "src_file", pending_task.posted_from.file_name(),
+        "src_func", pending_task.posted_from.function_name());
     pending_task.task.Run();
   }
 
@@ -107,7 +111,8 @@ bool WorkerPool::PostTask(const tracked_objects::Location& from_here,
 PosixDynamicThreadPool::PendingTask::PendingTask(
     const tracked_objects::Location& posted_from,
     const base::Closure& task)
-    : task(task) {
+    : posted_from(posted_from),
+      task(task) {
 }
 
 PosixDynamicThreadPool::PendingTask::~PendingTask() {
diff --git a/base/threading/worker_pool_posix.h b/base/threading/worker_pool_posix.h
index 990f50a..59593e2 100644
--- a/base/threading/worker_pool_posix.h
+++ b/base/threading/worker_pool_posix.h
@@ -55,6 +55,8 @@ class BASE_EXPORT PosixDynamicThreadPool
     // tracked_objects::TallyADeathIfActive() and
     // tracked_objects::TallyABirthIfActive correctly.
 
+    const tracked_objects::Location posted_from;
+
     // The task to run.
     base::Closure task;
   };
diff --git a/base/threading/worker_pool_win.cc b/base/threading/worker_pool_win.cc
index 2aa423f..b7eaad1 100644
--- a/base/threading/worker_pool_win.cc
+++ b/base/threading/worker_pool_win.cc
@@ -5,6 +5,7 @@
 #include "base/threading/worker_pool.h"
 
 #include "base/bind.h"
+#include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/task.h"
 #include "base/tracked_objects.h"
@@ -17,7 +18,8 @@ struct PendingTask {
   PendingTask(
       const tracked_objects::Location& posted_from,
       const base::Closure& task)
-      : task(task) {
+      : posted_from(posted_from),
+        task(task) {
 #if defined(TRACK_ALL_TASK_OBJECTS)
     post_births = tracked_objects::ThreadData::TallyABirthIfActive(posted_from);
     time_posted = TimeTicks::Now();
@@ -32,12 +34,18 @@ struct PendingTask {
   TimeTicks time_posted;
 #endif  // defined(TRACK_ALL_TASK_OBJECTS)
 
+  // The site this PendingTask was posted from.
+  tracked_objects::Location posted_from;
+
   // The task to run.
   base::Closure task;
 };
 
 DWORD CALLBACK WorkItemCallback(void* param) {
   PendingTask* pending_task = static_cast<PendingTask*>(param);
+  UNSHIPPED_TRACE_EVENT2("task", "WorkItemCallback::Run",
+                         "src_file", pending_task->posted_from.file_name(),
+                         "src_func", pending_task->posted_from.function_name());
   pending_task->task.Run();
 #if defined(TRACK_ALL_TASK_OBJECTS)
   tracked_objects::ThreadData::TallyADeathIfActive(