Update GN files w/ changes needed to make sanitizers work.

build/config/sanitizers/BUILD.gn

Index: build/config/sanitizers/BUILD.gn
diff --git a/build/config/sanitizers/BUILD.gn b/build/config/sanitizers/BUILD.gn
index 7dd3dd2e62029fb06b28726329d0200ba498e3e8..e05568b4c64f85cb76bd8c20d52aceec63257694 100644
--- a/build/config/sanitizers/BUILD.gn
+++ b/build/config/sanitizers/BUILD.gn
@@ -38,6 +38,20 @@ group("deps_no_options") {
       ":default_sanitizer_ldflags",
     ]
     deps = []
+
+    data = [
+      "//tools/valgrind/asan/",
+    ]
+    if (is_win) {
+      exe = ".exe"
+    } else {
+      exe = ""
+    }
+    data += [ "//third_party//llvm-build/Release+Asserts/bin/llvm-symbolizer${exe}" ]
+    if (is_linux) {
+      data += [ "//third_party/llvm-build/Release+Asserts/lib/libstdc++.so.6" ]

[Nico, 2016/06/02 18:16:41]

Can you add a comment here that says that this is needed by llvm-symbolizer?
(While libc++ is used for all of "our" binaries)

[Dirk Pranke, 2016/06/02 18:47:08]

Sure.

+    }
+
     if (use_prebuilt_instrumented_libraries) {
       deps += [ "//third_party/instrumented_libraries:deps" ]
     }
@@ -45,6 +59,7 @@ group("deps_no_options") {
       public_deps = [
         "//buildtools/third_party/libc++:libcxx_proxy",
       ]
+      data += [ "$root_out_dir/libc++.so" ]
     }
     if (is_mac) {
       data_deps = [
@@ -158,6 +173,14 @@ config("common_sanitizer_flags") {
     cflags += [ "-gline-tables-only" ]
   }
 
+  if (symbolized) {
+    cflags += [

[Nico, 2016/06/02 18:16:41]

What's the motivation for this block? I can't find the corresponding bit in gyp.

(I can find
https://code.google.com/p/chromium/codesearch#chromium/src/build/common.gypi&...
for tsan which is probably still missing here?)

[Dirk Pranke, 2016/06/02 18:47:08]

These flags get passed directly in the 'release_extra_cflags' value of
GYP_DEFINES on the "symbolized" bots on chromium.lkgr, e.g.:

https://build.chromium.org/p/chromium.lkgr/builders/ASAN%20Release%20%28symbo...

I think the release_extra_cflags escape valve is a misfeature, which is why I
added the 'symbolized' config to MB and the GN files.

I'll look at the gyp block and see what might need to be merged in.

+      "-O1",

[Nico, 2016/06/02 18:16:41]

Wouldn't the gn way for this be to pick a different default optimization level
in the compiler config if symbolized is set, instead of adding -O1 here?
Depending on config ordering, this -O1 might be before or after the -O flag from
the compiler config. Since the last flag wins, it's not clear if this will have
an effect.

[Dirk Pranke, 2016/06/02 18:47:08]

Hm, probably. Good catch. I'll look at reworking this.

+      "-fno-line-functions",

[Nico, 2016/06/02 18:16:41]

This is supposed to be -fno-inline-functions I assume

[Dirk Pranke, 2016/06/02 18:47:08]

Yup, that's a typo. Another good catch.

+      "-fno-inline",
+    ]
+  }
+
   # Common options for AddressSanitizer, LeakSanitizer, ThreadSanitizer,
   # MemorySanitizer and non-official CFI builds.
   if (using_sanitizer || (is_cfi && !is_official_build)) {