Set appropriate working directory on build failure

tools/bisect-perf-regression.py

Index: tools/bisect-perf-regression.py
diff --git a/tools/bisect-perf-regression.py b/tools/bisect-perf-regression.py
index 9536f6c35016057dbe7cb881128eb2605e374431..67097ed1233e76cf916733fe8eb77c001c544c90 100755
--- a/tools/bisect-perf-regression.py
+++ b/tools/bisect-perf-regression.py
@@ -1525,6 +1525,8 @@ class BisectPerformanceMetrics(object):
     """
     if self.opts.debug_ignore_build:
       return True
+
+    build_success = False
     cwd = os.getcwd()

[qyearsley, 2014/09/09 00:59:57]

(Note, somewhat unrelated to this CL: this variable name could probably be
improved. cwd stands for "current working directory", and once you chdir away
from it, it's no longer the current working directory... same goes for
"src_cwd". Should probably just be called "src_dir".)

     os.chdir(self.src_cwd)
     # Fetch build archive for the given revision from the cloud storage when
@@ -1535,16 +1537,14 @@ class BisectPerformanceMetrics(object):
         # Create a DEPS patch with new revision for dependency repository.
         revision, deps_patch = self.CreateDEPSPatch(depot, revision)
       if self.DownloadCurrentBuild(revision, patch=deps_patch):
-        os.chdir(cwd)
         if deps_patch:
           # Reverts the changes to DEPS file.
           self.source_control.CheckoutFileAtRevision(
               bisect_utils.FILE_DEPS, revision, cwd=self.src_cwd)
-        return True
-      return False
-
-    # These codes are executed when bisect bots builds binaries locally.
-    build_success = self.builder.Build(depot, self.opts)
+        build_success = True
+    else:
+      # These codes are executed when bisect bots builds binaries locally.
+      build_success = self.builder.Build(depot, self.opts)
     os.chdir(cwd)
     return build_success