Add several new TRACE call and UMA metrics for GetProfile()

chrome/browser/profiles/profile_impl.cc

Index: chrome/browser/profiles/profile_impl.cc
diff --git a/chrome/browser/profiles/profile_impl.cc b/chrome/browser/profiles/profile_impl.cc
index 4fcb7e476868d7a0b1bcfdf970ca424aa082f8fc..0144d4f025f72fea60cc7220d3aca56fc3c244b8 100644
--- a/chrome/browser/profiles/profile_impl.cc
+++ b/chrome/browser/profiles/profile_impl.cc
@@ -15,6 +15,7 @@
 #include "base/files/file_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "base/prefs/json_pref_store.h"
 #include "base/prefs/scoped_user_pref_update.h"
@@ -266,10 +267,10 @@ PrefStore* CreateExtensionPrefStore(Profile* profile,
 Profile* Profile::CreateProfile(const base::FilePath& path,
                                 Delegate* delegate,
                                 CreateMode create_mode) {
-  TRACE_EVENT_BEGIN1("browser",
-                     "Profile::CreateProfile",
-                     "profile_path",
-                     path.value().c_str());
+  TRACE_EVENT1("browser,startup",
+               "Profile::CreateProfile",
+               "profile_path",
+               path.MaybeAsASCII());

[Alexei Svitkine (slow), 2015/02/18 21:48:03]

What happens if the path is not ASCII?

From the header docs:

"This should only be used for cases where the FilePath is representing a
known-ASCII filename."

This doesn't seem like the case here. I think a safe UTF8 conversion should be
done.

[rkaplow, 2015/02/19 00:18:57]

If it is not ASCII then it returns the empty string, which is not so bad:
https://code.google.com/p/chromium/codesearch#chromium/src/base/files/file_pa...
Worst case, you just don't see the arg in the trace.

all the UTC method have 'unsafe' in the name. Do you have a link for how to
convert to UTF8 safely?

[Alexei Svitkine (slow), 2015/02/19 14:44:58]

According to the comment for AsUTF8Unsafe(), it's only unsafe non-Mac, non-CrOS
POSIX systems - and only then diminishingly so - i.e. only on systems that don't
use utf8.

So I think using that is fine here. Though I'm also OK with MaybeAsASCII() per
your explanation above, with a slight preference for utf8.

 
   // Get sequenced task runner for making sure that file operations of
   // this profile (defined by |path|) are executed in expected order
@@ -282,8 +283,8 @@ Profile* Profile::CreateProfile(const base::FilePath& path,
     CreateProfileDirectory(sequenced_task_runner.get(), path);
   } else if (create_mode == CREATE_MODE_SYNCHRONOUS) {
     if (!base::PathExists(path)) {
-      // TODO(tc): http://b/1094718 Bad things happen if we can't write to the
-      // profile directory.  We should eventually be able to run in this
+      // TODO(): http://crbug/160553 - Bad things happen if we can't write to
+      // the profile directory.  We should eventually be able to run in this
       // situation.
       if (!base::CreateDirectory(path))
         return NULL;
@@ -411,7 +412,7 @@ ProfileImpl::ProfileImpl(
       start_time_(Time::Now()),
       delegate_(delegate),
       predictor_(NULL) {
-  TRACE_EVENT0("browser", "ProfileImpl::ctor")
+  TRACE_EVENT0("browser,startup", "ProfileImpl::ctor")
   DCHECK(!path.empty()) << "Using an empty path will attempt to write " <<
                             "profile files to the root directory!";
 
@@ -666,12 +667,6 @@ void ProfileImpl::DoFinalInit() {
   // as a URLDataSource early.
   RegisterDomDistillerViewerSource(this);
 
-  // Creation has been finished.
-  TRACE_EVENT_END1("browser",
-                   "Profile::CreateProfile",
-                   "profile_path",
-                   path_.value().c_str());
-
 #if defined(OS_CHROMEOS)
   if (chromeos::UserSessionManager::GetInstance()
           ->RestartToApplyPerSessionFlagsIfNeed(this, true)) {
@@ -848,7 +843,8 @@ ExtensionSpecialStoragePolicy*
 }
 
 void ProfileImpl::OnPrefsLoaded(bool success) {
-  TRACE_EVENT0("browser", "ProfileImpl::OnPrefsLoaded")
+  TRACE_EVENT0("browser", "ProfileImpl::OnPrefsLoaded");
+  SCOPED_UMA_HISTOGRAM_TIMER("Profile.OnPrefsLoadedTime");
   if (!success) {
     if (delegate_)
       delegate_->OnProfileCreated(this, false, false);