Re-enable dynamic NEON support in Skia.

The Skia build depends on arm_neon_optional=1 being defined in GYP_DEFINES
to enable dynamic NEON support. It looks like this option was lost in
translation during the upstreaming of build/android/.

Note that this won't fix crbug.com/161834, i.e. on JB and higher, the
sandboxing currently prevents the CPU feature detection from working, but
it's a first step in the right direction (it fixes the code for ICS devices
though).

BUG=164002

R=joth@chromium.org,torne@chromium.org,djsollen@chromium.org,tomhudson@chromium.org,reed@chromium.org


Review URL: https://chromiumcodereview.appspot.com/11419299

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@171001 0039d316-1c4b-4281-b951-d872f2087c98

build/android/envsetup_functions.sh

@@ -111,6 +111,7 @@ common_vars_defines() {
   case "${TARGET_ARCH}" in
     "arm")
       DEFINES+=" arm_neon=0 armv7=1 arm_thumb=1 arm_fpu=vfpv3-d16"
+      DEFINES+=" arm_neon_optional=1"  # Enable dynamic NEON support.
       DEFINES+=" ${ORDER_DEFINES}"
       DEFINES+=" target_arch=arm"
       ;;