Replace system IO calls in chromecast/crash with Chrome utilities.

chromecast/crash/linux/crash_util.cc

Index: chromecast/crash/linux/crash_util.cc
diff --git a/chromecast/crash/linux/crash_util.cc b/chromecast/crash/linux/crash_util.cc
index e80b179c16e35d8f2292fd0892a9303563ac97a9..d9b434f4a9bc3da2744a5ae7b607cb0b54ecf38b 100644
--- a/chromecast/crash/linux/crash_util.cc
+++ b/chromecast/crash/linux/crash_util.cc
@@ -4,10 +4,10 @@
 
 #include "chromecast/crash/linux/crash_util.h"
 
-#include <stdlib.h>
-
 #include "base/bind.h"
 #include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
 #include "chromecast/base/path_utils.h"
 #include "chromecast/base/version.h"
@@ -37,12 +37,13 @@ bool CrashUtil::RequestUploadCrashDump(
     const std::string& existing_minidump_path,
     const std::string& crashed_process_name,
     uint64_t crashed_process_start_time_ms) {
+  // Remove IO restrictions from this thread. Chromium IO functions must be used
+  // to access the file system and upload information to the crash server.
+  base::ThreadRestrictions::SetIOAllowed(true);

[gfhuang, 2015/07/16 18:39:59]

this has to be scopedIO or you need to SetIOAllowed(false) when it all ends.

[gunsch, 2015/07/16 18:49:18]

ScopedAllowIO is banned.

I think this is only used in the context of while we're actively crashing,
right? If not, we should definitely SetIOAllowed(true) afterwards.

[wzhong, 2015/07/16 18:52:19]

SetIOAllowed() returns previous state.

Save it and call SetIOAllowed() again afterwards.

[wzhong, 2015/07/16 18:52:19]

SetIOAllowed() returns previous state.

Save it and call SetIOAllowed() again.

[wzhong, 2015/07/16 18:54:18]

It should be used only around base::Move().

[gfhuang, 2015/07/16 18:57:01]

We need to set it back to false then.

This could be called in browser process when rendered process is crashed.
so browser process is still alive after all these ends.

[gfhuang, 2015/07/16 18:57:01]

+1, the process could be alive after these (browser process for example)
so need to restore the value.
base:FileExists also needs it.

[slan, 2015/07/16 20:06:24]

I was not aware that this could be posted to the UI thread, for example. Done.
I set and remove the permissions in the top-level function, rather than wrapping
each call individually. This will be beneficial when many other Chrome IO calls
are substituted for existing system calls in future CLs. (Most notably in
SynchronizedMinidumpManager)

+
   LOG(INFO) << "Request to upload crash dump " << existing_minidump_path
             << " for process " << crashed_process_name;
 
-  // Note: Do not use Chromium IO methods in this function. When cast_shell
-  // crashes, this function can be called by any thread, which may not allow IO.
-  // Use stdlib system calls for IO instead.
   uint64_t uptime_ms = GetCurrentTimeMs() - crashed_process_start_time_ms;
   MinidumpParams params(crashed_process_name,
                         uptime_ms,
@@ -68,10 +69,11 @@ bool CrashUtil::RequestUploadCrashDump(
   writer->set_non_blocking(false);
   success = (0 == writer->Write());  // error already logged.
 
-  // In case the file is still in $TEMP, remove it.
-  if (remove(existing_minidump_path.c_str()) < 0 && errno != ENOENT) {
+  // In case the file is still in $TEMP, remove it. Note that DeleteFile() will
+  // return true if |existing_minidump_path| has already been moved.
+  if (!base::DeleteFile(base::FilePath(existing_minidump_path), false)) {
     LOG(ERROR) << "Unable to delete temp minidump file "
-               << existing_minidump_path << ": " << strerror(errno);
+               << existing_minidump_path;
     success = false;
   }