Roll ICU to 53046 to grab my use_system_icu gyp updates.

TBR=jshin

TEST=none
BUG=28294

Review URL: http://codereview.chromium.org/3010017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@53047 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -34,7 +34,7 @@ deps = {
     "/trunk/deps/third_party/WebKit@33467",
 
   "src/third_party/icu":
-    "/trunk/deps/third_party/icu42@51076",
+    "/trunk/deps/third_party/icu42@53046",
 
   "src/third_party/hunspell":
    "/trunk/deps/third_party/hunspell@51690",