Orderfile: better pregenerated profile handling.

Use pregenerated profiles for system health orderfiles, and
avoid compiling if they are being used.

Change-Id: Ib386bcd227e4f3ee4892d50ea2ec41085497f41b
Reviewed-on: https://chromium-review.googlesource.com/c/1332299
Commit-Queue: Matthew Cary <mattcary@chromium.org>
Reviewed-by: Egor Pasko <pasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607544}

diff --git a/tools/cygprofile/orderfile_generator_backend.py b/tools/cygprofile/orderfile_generator_backend.py
index 877b8f94..543cd94 100755
--- a/tools/cygprofile/orderfile_generator_backend.py
+++ b/tools/cygprofile/orderfile_generator_backend.py

@@ -707,7 +707,11 @@
             self._options.max_load, self._options.use_goma,
             self._options.goma_dir, self._options.system_health_orderfile,
             self._options.monochrome)
-        self._compiler.CompileChromeApk(True)
+        if not self._options.pregenerated_profiles:
+          # If there are pregenerated profiles, the instrumented build should
+          # not be changed to avoid invalidating the pregenerated profile
+          # offsets.
+          self._compiler.CompileChromeApk(True)
         self._GenerateAndProcessProfile()
         self._MaybeArchiveOrderfile(self._GetUnpatchedOrderfileFilename())
         profile_uploaded = True