Instrumented libraries: allow GOMA with a custom compiler.

BUG=none
R=glider@chromium.org

Review URL: https://codereview.chromium.org/1038883002

Cr-Commit-Position: refs/heads/master@{#322389}

third_party/instrumented_libraries/instrumented_libraries.gyp

@@ -6,14 +6,12 @@
   'variables': {
     'verbose_libraries_build%': 0,
     'instrumented_libraries_jobs%': 1,
-    'instrumented_libraries_cc%': '',
-    'instrumented_libraries_cxx%': '',
+    'instrumented_libraries_cc%': '<!(cd <(DEPTH) && pwd -P)/<(make_clang_dir)/bin/clang',
+    'instrumented_libraries_cxx%': '<!(cd <(DEPTH) && pwd -P)/<(make_clang_dir)/bin/clang++',
   },
 
   'libdir': 'lib',
   'ubuntu_release': '<!(lsb_release -cs)',
-  'clang_absolute_path': '<!(cd <(DEPTH) && pwd -P)/<(make_clang_dir)/bin/clang',
-  'clang++_absolute_path': '<!(cd <(DEPTH) && pwd -P)/<(make_clang_dir)/bin/clang++',
 
   'conditions': [
     ['asan==1', {
@@ -26,18 +24,10 @@
       'sanitizer_type': 'tsan',
     }],
     ['use_goma==1', {
-      'cc': '<(gomadir)/gomacc <(_clang_absolute_path)',
-      'cxx': '<(gomadir)/gomacc <(_clang++_absolute_path)',
+      'cc': '<(gomadir)/gomacc <(instrumented_libraries_cc)',
+      'cxx': '<(gomadir)/gomacc <(instrumented_libraries_cxx)',
     }, {
-      'cc': '<(clang_absolute_path)',
-      'cxx': '<(clang++_absolute_path)',
-    }],
-    # When building with a custom clang, CC/CXX must be overridden via GYP
-    # variables.
-    ['instrumented_libraries_cc!=""', {
       'cc': '<(instrumented_libraries_cc)',
-    }],
-    ['instrumented_libraries_cxx!=""', {
       'cxx': '<(instrumented_libraries_cxx)',
     }],
   ],