[test] Make msan work for v8 stand-alone.

The msan configuration can be used in combination with
v8_use_snapshot=false.

BUG=chromium:425187
LOG=n

Review URL: https://codereview.chromium.org/802583003

Cr-Commit-Position: refs/heads/master@{#28064}

build/standalone.gypi

@@ -35,6 +35,10 @@
     'component%': 'static_library',
     'clang_dir%': 'third_party/llvm-build/Release+Asserts',
     'clang_xcode%': 0,
+    # Track where uninitialized memory originates from. From fastest to
+    # slowest: 0 - no tracking, 1 - track only the initial allocation site, 2
+    # - track the chain of stores leading from allocation site to use site.
+    'msan_track_origins%': 1,
     'visibility%': 'hidden',
     'v8_enable_backtrace%': 0,
     'v8_enable_i18n_support%': 1,
@@ -315,6 +319,36 @@
         ],
       },
     }],
+    ['msan==1 and OS!="mac"', {
+      'target_defaults': {
+        'cflags_cc+': [
+          '-fno-omit-frame-pointer',
+          '-gline-tables-only',
+          '-fsanitize=memory',
+          '-fsanitize-memory-track-origins=<(msan_track_origins)',
+          '-fPIC',
+        ],
+        'cflags+': [
+          '-fPIC',
+        ],
+        'cflags!': [
+          '-fno-exceptions',
+          '-fomit-frame-pointer',
+        ],
+        'ldflags': [
+          '-fsanitize=memory',
+        ],
+        'defines': [
+          'MEMORY_SANITIZER',
+        ],
+        'dependencies': [
+          # Use libc++ (third_party/libc++ and third_party/libc++abi) instead of
+          # stdlibc++ as standard library. This is intended to use for instrumented
+          # builds.
+          '<(DEPTH)/buildtools/third_party/libc++/libc++.gyp:libcxx_proxy',
+        ],
+      },
+    }],
     ['asan==1 and OS=="mac"', {
       'target_defaults': {
         'xcode_settings': {