travis: add a clang build

We rework the matrix a bit to avoid the implicit explosion of
duplicated results.

Change-Id: I9a2d91b3a6a55bf2843e0e90d59fe5710bd639c7
Reviewed-on: https://chromium-review.googlesource.com/444544
Reviewed-by: Ted Mielczarek <ted@mielczarek.org>

.travis.yml

@@ -2,33 +2,31 @@
 # https://docs.travis-ci.com/
 language: cpp
 
-# Order here matters for implicit matrix generation and coverity scan.
-# See scripts/travis-build.sh for details.
-# TODO: add a clang build as well.
-compiler:
- - gcc
 addons:
   apt:
     sources:
       - ubuntu-toolchain-r-test
     packages:
+      - clang
       - gcc-4.8
       - g++-4.8
-# Travis sets CC/CXX to the system toolchain based on the `compiler`
-# selection. If clang is added, this should move to be set inside the
-# matrix.
+
 env:
   global:
     - secure: "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"
-  matrix:
-    - USE_CC=gcc-4.8 USE_CXX=g++-4.8
+
+# TODO: Add an OS X config.
+matrix:
+  include:
+    - os: linux
+      compiler: gcc
+      env: USE_CC=gcc-4.8 USE_CXX=g++-4.8 COVERITY_SCAN=true
+    - os: linux
+      compiler: clang
+
 before_install: ./scripts/travis-checkout.sh
 script: ./scripts/travis-build.sh
 
-# Order here matters; see compiler comment above.
-# TODO: add mac support
-os:
-  - linux
 notifications:
   email:
     - google-breakpad-dev@googlegroups.com

scripts/travis-build.sh

@@ -24,7 +24,7 @@ setup_env() {
 # We also do it by hand because when we're throttled, the addon will exit
 # the build immediately and skip the main script!
 coverity_scan() {
-  if [ "${TRAVIS_JOB_NUMBER##*.}" != "1" ] || \
+  if [ "${COVERITY_SCAN}" != "true" ] || \
      [ -n "${TRAVIS_TAG}" ] || \
      [ "${TRAVIS_PULL_REQUEST}" = "true" ]
   then