v8: upgrade to v3.19.3

deps/v8/ChangeLog

@@ -1,3 +1,30 @@
+2013-05-22: Version 3.19.3
+
+        Performance and stability improvements on all platforms.
+
+
+2013-05-17: Version 3.19.2
+
+        Fill in one-word-fillers for the unused property fields
+        (Chromium issue 240056).
+
+        Removed use_system_v8 logic from the mainline gyp file
+        (Chromium issue 226860).
+
+        Skip CPU profiler samples where top function's stack frame is not
+        set up properly (issue 2628).
+
+        Performance and stability improvements on all platforms.
+
+
+2013-05-14: Version 3.19.1
+
+        Fixed missing hole check for loads from Smi arrays when all uses are
+        changes (Chromium issue 233737)
+
+        Performance and stability improvements on all platforms.
+
+
 2013-05-10: Version 3.19.0
 
         Deprecated Context::New which returns Persistent.

deps/v8/build/common.gypi

@@ -29,7 +29,6 @@
 
 {
   'variables': {
-    'use_system_v8%': 0,
     'msvs_use_common_release': 0,
     'gcc_version%': 'unknown',
     'CXX%': '${CXX:-$(which g++)}',  # Used to assemble a shell command.
@@ -454,6 +453,15 @@
           }],
           ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="netbsd" \
             or OS=="android"', {
+            'cflags!': [
+              '-O2',
+              '-Os',
+            ],
+            'cflags': [
+              '-fdata-sections',
+              '-ffunction-sections',
+              '-O3',
+            ],
             'conditions': [
               [ 'gcc_version==44 and clang==0', {
                 'cflags': [