Add ui build to travis

Rolls recompiled emsdk-llvm, build as follows:

$ export LLVM_CMAKE_ARGS='-DCMAKE_MODULE_LINKER_FLAGS=-static-libstdc++,-DCMAKE_EXE_LINKER_FLAGS=-static-libstdc++'
$ ./emsdk install clang-tag-e1.37.40-64bit
$ ./emsdk install binaryen-tag-1.37.40-64bit
$ echo "-DCMAKE_MODULE_LINKER_FLAGS=-static-libstdc++ -DCMAKE_EXE_LINKER_FLAGS=-static-libstdc++" >> binaryen/tag-1.37.40_64bit_binaryen/recmake.sh
$ binaryen/tag-1.37.40_64bit_binaryen/recmake.sh
$ mkdir dist
$ cp -a clang/tag-e1.37.40/build_tag-e1.37.40_64/bin dist/
$ cp -a binaryen/tag-1.37.40_64bit_binaryen/ dist/binaryen
$ tar -zcf llvm.tar.gz dist

Change-Id: I29ad70d344e4e4f6ca40605fd6ff15a05c0fc9a4
diff --git a/tools/install-build-deps b/tools/install-build-deps
index 9af833c..2b53158 100755
--- a/tools/install-build-deps
+++ b/tools/install-build-deps
@@ -215,8 +215,8 @@
    'darwin'
   ),
   ('buildtools/emsdk/llvm.tgz',
-   'https://storage.googleapis.com/perfetto/emscripten-llvm-e1.37.40-linux.tar.gz',
-   'fdc26481fe70001ea00e83b99d0df906c9b2a45f',
+   'https://storage.googleapis.com/perfetto/emscripten-llvm-e1.37.40-static-linux.tar.gz',
+   '478501b9b7a14884e546c84efe209a90052cbb07',
    'linux2'
   ),
 ]