Fix segmentation fault in trace_subscriber_stdio.cc.

This is part of Chrome for Android upstreaming.

This crash happens when the output trace file can't be opened. It is due to the
trace buffer's output callback not being set in case the file can't be opened.
Even if TraceResultBuffer::Start() is not called, the output callback still
needs to be set since it is used by TraceResultBuffer::AddFragment().

BUG=152867

Review URL: https://chromiumcodereview.appspot.com/11038062

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@160669 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 3 insertions, 3 deletions

diff --git a/content/browser/trace_subscriber_stdio.cc b/content/browser/trace_subscriber_stdio.cc
index a102810..05ebaba 100644
--- a/content/browser/trace_subscriber_stdio.cc
+++ b/content/browser/trace_subscriber_stdio.cc
@@ -22,11 +22,11 @@ class TraceSubscriberStdioImpl
 
   void OnStart() {
     DCHECK(!file_);
+    trace_buffer_.SetOutputCallback(
+        base::Bind(&TraceSubscriberStdioImpl::Write, this));
     file_ = file_util::OpenFile(path_, "w+");
     if (IsValid()) {
       LOG(INFO) << "Logging performance trace to file: " << path_.value();
-      trace_buffer_.SetOutputCallback(
-          base::Bind(&TraceSubscriberStdioImpl::Write, this));
       trace_buffer_.Start();
     } else {
       LOG(ERROR) << "Failed to open performance trace file: " << path_.value();
@@ -49,7 +49,7 @@ class TraceSubscriberStdioImpl
     CloseFile();
   }
 
-  bool IsValid() {
+  bool IsValid() const {
     return file_ && (0 == ferror(file_));
   }