[Mac] address perf regressions on bots

This isn't the prettiest, but it should get the perf back where we want it.  If the file we're asked to exclude is in /var or /private, ignore it.  The problem on the bots is the TimeMachine prefs plist is growing unbounded as we keep adding 4 files each run for temporary profiles.  The load/modify/write gets slower with each addition.  This quick/dirty check to avoid that.  Since the original bug for the backup of this data is still open, I figure landing this is the right thing to do until that is fully addressed.

BUG=25959,30002
TEST=page cycles, browser_tests all get back to being fast.  normal profiles still exclude the files listed in the first bug.
Review URL: http://codereview.chromium.org/523024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@35382 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 13 insertions, 0 deletions

diff --git a/base/mac_util.mm b/base/mac_util.mm
index f585233..f6d5dff 100644
--- a/base/mac_util.mm
+++ b/base/mac_util.mm
@@ -240,6 +240,19 @@ FilePath GetAppBundlePath(const FilePath& exec_name) {
 bool SetFileBackupExclusion(const FilePath& file_path, bool exclude) {
   NSString* filePath =
       [NSString stringWithUTF8String:file_path.value().c_str()];
+
+  // If being asked to exclude something in a temp directory, just lie and say
+  // it was done.  TimeMachine will already ignore temp directories.  This keeps
+  // the temporary profiles used by unittests from being added to the exclude
+  // list.  Otherwise, as the list grows the bots slow down due to
+  // reading/writes all the temporary profiles used over time.
+  if ([filePath hasPrefix:@"/tmp/"] ||
+      [filePath hasPrefix:@"/var/tmp/"] ||
+      [filePath hasPrefix:@"/private/tmp/"] ||
+      [filePath hasPrefix:@"/private/var/tmp/"]) {
+    return true;
+  }
+
   NSURL* url = [NSURL fileURLWithPath:filePath];
   // Note that we always set CSBackupSetItemExcluded's excludeByPath param
   // to true.  This prevents a problem with toggling the setting: if the file