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

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index b25c5338f542ca29c94912d45c56f19e75b9bfe9..6d8bb148d273f45f0aaccf150b79e3cda0cf640b 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -632,8 +632,7 @@
       #                  http://crbug.com/105550
       'use_canvas_skia%': 0,
 
-      # Set to "tsan", "memcheck", or "drmemory" to configure the build to work
-      # with one of those tools.
+      # Set to "drmemory" to configure the build to work with DrMemory.
       'build_for_tool%': '',
 
       'wix_path%': '<(DEPTH)/third_party/wix',
@@ -2285,27 +2284,6 @@
         'v8_target_arch': 'arm64',
       }],
 
-      # On valgrind bots, override the optimizer settings so we don't inline too
-      # much and make the stacks harder to figure out.
-      #
-      # TODO(rnk): Kill off variables that no one else uses and just implement
-      # them under a build_for_tool== condition.
-      ['build_for_tool=="memcheck" or build_for_tool=="tsan"', {

[Dirk Pranke, 2016/06/03 04:17:29]

The best we can tell, "memcheck" is now gone (no more valgrind bots) and it's
unclear whether we ever used build_for_tool="tsan", but we don't now, so this
whole block was dead code.

[krasin, 2016/06/03 04:43:51]

I confirm that (spoken with eugenis@)

-        # gcc flags
-        'mac_debug_optimization': '1',
-        'mac_release_optimization': '1',
-        'release_optimize': '1',
-        'no_gc_sections': 1,
-        'debug_extra_cflags': '-g -fno-inline -fno-omit-frame-pointer '
-                              '-fno-builtin -fno-optimize-sibling-calls',
-        'release_extra_cflags': '-g -fno-inline -fno-omit-frame-pointer '
-                                '-fno-builtin -fno-optimize-sibling-calls',
-
-        'release_valgrind_build': 1,
-        'werror': '',
-        'component': 'static_library',
-      }],
-
       # Build tweaks for DrMemory.
       # TODO(rnk): Combine with tsan config to share the builder.
       # http://crbug.com/108155